Reconstruction of the biogeochemistry and ecology of photoautotrophs based on the nitrogen and carbon isotopic compositions of vanadyl porphyrins from Miocene siliceous sediments

We determined both the nitrogen and carbon isotopic compositions of various vanadyl alkylporphyrins isolated from siliceous marine sediments of the Onnagawa Formation (middle Miocene, northeastern Japan) to investigate the biogeochemistry and ecology of photoautotrophs living in the paleo-ocean. The distinctive isotopic signals support the interpretations of previous works that the origin of 17-nor-deoxophylloerythroetioporphyrin (DPEP) is chlorophylls-<i>c</i><sub>1-3</sub>, whereas 8-nor-DPEP may have originated from chlorophylls-<i>a</i><sub>2</sub> or <i>b</i><sub>2</sub> or bacteriochlorophyll-<i>a</i>. Although DPEP and cycloheptanoDPEP are presumably derived from common precursory pigments, their isotopic compositions differed in the present study, suggesting that the latter represents a specific population within the photoautotrophic community. The average δ<sup>15</sup>N value for the entire photoautotrophic community is estimated to be –2 to +1‰ from the δ<sup>15</sup>N values of DPEP (–6.9 to –3.6‰; <i>n</i>=7), considering that the empirical isotopic relationships that the tetrapyrrole nuclei of chloropigments are depleted in <sup>15</sup>N by ~4.8‰ and enriched in <sup>13</sup>C by ~1.8‰ relative to the whole cells. This finding suggests that nitrogen utilized in the primary production was supplied mainly through N<sub>2</sub>-fixation by diazotrophic cyanobacteria. Based on the δ<sup>13</sup>C values of DPEP (–17.9 to –15.6‰; <i>n</i>=7), we estimated isotopic fractionation associated with photosynthetic carbon fixation to be 8–14‰. This range suggests the importance of β-carboxylation and/or active transport of the carbon substrate, indicating in turn the substantial contribution of diazotrophic cyanobacteria to primary production. Based on the δ<sup>15</sup>N values of 17-nor-DPEP (–7.4 to –2.4‰ <i>n</i>=7), the δ<sup>15</sup>N range of chlorophylls-<i>c</i>-producing algae was estimated to be –3 to +3‰. This relative depletion in sup>15</sup>N suggests that these algae mainly utilized nitrogen regenerated from diazotrophic cyanobacteria. Given that diatoms are likely to have constituted the chlorophylls-<i>c</i>-producing algae within the biogenic-silica-rich Onnagawa Formation, cyanobacteria-hosting diatoms may have been important contributors to primary production

Electron Diffraction Study on Titanium Attacked by Various Acids

Titanium immersed in various acids were examined by electron diffraction. Surfaces attacked by hydrofluoric, hydrochloric, sulphuric or phosphoric acid suffered considerable corrosion and yielded Debye rings of a face-centred cubic lattice, which was deduced as belong to titanium hydride (TiH_2) formed in the course of corrosion. At the surfaces immersed in nitric acid at room temperature for a long period, however, hexagonal rings of titanium alone were observed, and these surfaces were taken as the standard for further corrosion tests. In the following cases the surfaces became passive, and protective films were formed : When the specimens were attacked by boiling nitric acid or aqua regia, anatase was formed, while a mixture of this and a rutile was seen after immersion in boiling 10 per cent solution of chromic acid. The surfaces immersed in boiling 10 per cent solution of ferric chloride for 1 hour yielded many sharp rings, which, however, could not be assigned to any known compound of titanium at the present stage

<原著>副腎腫瘤の臨床的検討

We reviewed the records of 13 patients with adrenal masses operated on over a ten-year period to clarify clinical characteristics of adrenal tumors. Tumors were found incidentally in seven of nine patients with primary adrenal tumors (78%); however, three of these seven patients (43%) proved to have shown symptoms related to adrenal hyperfunction when re-e、raluated. Other adrenal tumors (metastatic in three patients and inflammatory in one) were found without any symptoms referable to the tumors. In nine of 13 patients (69%), tumors were discovered by computerized tomography (CT). All patients with primary tumors have been gotten free of disease postoperatively. In contrast, although all three patients with metastatic adrenal tumors underwent resection of all known disease tissue, they died of the recurrence of malignancies within 10 months. This study suggests that a number of functional adrenal tumors are possibly left undiagnosed until found incidentally, and that CT is the most powerful tool to detect adrenal tumors. Our data did not support surgical intervention in cases of metastatic adrenal tumors.副腎腫瘤の臨床的特徴を明らかにするために過去10年間に当科で手術された13例を検討した. 原発性腫瘍9例中2例は臨床症状より原発性アルドステロン症を疑われ副腎腫瘍を発見されているが, 残りの7例(78%)は偶然腫瘍が発見された, いわゆる incidentaloma であった. しかしながら, retrospective にみるとこの7例中3例(43%)で副腎機能亢進によると考えられる症状を呈していた. 転移性腫瘍3例, histoplasma による肉芽腫1例は全て無症状であった. 13例中9例(69%)はCTにより, 2例は超音波, 1例は血管造影, 1例は scintigraphy によりそれぞれ病変を発見され, CT で副腎腫瘤を指摘できなかったのは1例のみであった. 13例中11例は経腹的に, 2例 は開胸開腹で手術されたが, 術後合併症は1例に創感染を認めたのみであった. 原発性腫瘍例は全例術後再発を認めていないが, 転移性腫瘍の3例は全例, 術後10ヶ月以内に再発死した. 以上の結果は機能性副腎腫瘍でも偶然発見されるまで診断されない場合が多いことを示唆しており, 臨床症状を注意深く検討し常に副腎腫瘍の可能性を考慮にいれることが肝要であると考えられる. また, 今回の結果より CT が副腎腫瘤の診断において重要な位置を占めるものと考えられた. なお, 転移性副腎腫瘍に対する手術療法は今回の検討ではそれを積極的に支持する結果は得られず, 今後さらに検討を要する問題と思われる

Study on Precipitation Phenomena during Aging of Aluminium-Silver Alloy in Thin Evaporated Films

Precipitation phenomena during aging have been observed on aluminium-20 wt. per cent silver alloy in thin evaporated films by electron microscopy and electron diffraction. A super-saturated solid solution has successfully been obtained in thin films by a new quenching method. In a preprecipitation stage aggregates composed of random clusters have been found in electron micrographs, no appreciable diffraction effect having been perceived. In a true precipitation stage precipitates have been found in electron micrographs to change from a needle-like to a three dimensional shape with increasing aging, the axial ratio obtained from diffraction patterns changing from 1.63_3 to 1.59 passing 1.61_2. It is a merit of the present study that a hexagonal precipitate with the ideal axial ratio has been detected in the course of aging. Except this point, the results obtained confirm generally those reported by X-ray studies. So-called "equal-thickness interference fringes" have been found in images of precipitates aged at 250℃

Electron Diffraction Study on Nickel Surfaces Tarnished in the Course of Heat-Treatment in Hydrogen

When nickel plates for vacuum tubes are annealed in hydrogen gas at 900～1000℃ in the process of production, their surfaces often tarnish and show milk-white appearance, which considerably lowers their commercial value. In order to infer the cause of this tarnishing, six kinds of plates were selected and their surfaces were examined by electron diffraction after heat-treatment. Milk-white surfaces generally gave diffuse rings which were entirely different from the nickel pattern. Three specimens did not alter their appearances after the treatment. One of them gave a few diffuse rings and elongated spots, while the other two, one of which was made in U.S.A., yielded many comparatively sharp rings. According to our analyses, the rings obtained from the two milk-white surfaces were due to (Mg, Ca) SiO_3 and NiO, and those from the two lustrous surfaces beloriged to nickel and Mg_2SiO_4 in one case and to nickel, MnO, MnS and NiO or to nickel, Mg_2SiO_4, MnO and NiO in the other case. From the fact that a greater part of diffraction rings of the milk-white surfaces could be explained as being due to (Mg, Ca) SiO_3, It was concluded that the tarnishing was due to silicates of light metals. Silicates like (Mg, Ca) SiO_3 and Mg_2SiO_4 must be removed during melting, and if a small quantity of them remains and even though disperses over the whole material, it may gradually aggregate in grain boundaries at the heat-treatment, which finally causes the tarnishing of surfaces

Electron Diffraction Study on Diffuse Scattering from Disordered Cu_3Au Alloy

A detailed study has been made on diffuse scattering from Cu_3Au alloy in the disordered state by electron diffraction, using single crystal evaporated films, in order to investigate the origin of the short-range order above T_c. Aspects of the diffuse scattering resemble in some respects those of superlattice reflections below T_c, which are related to the antiphase domain structure. From the present study, however, it has become clear that there is no direct relation between the short-range order state above Te and the antiphase domain structure below T_c. Behaviors of the diffuse scattering have been studied, the electron-atom ratio being changed by addition of Pd or In to Cu_3Au. Results obtained are well interpreted by the suggestion of Moss, indicating that the short-range order state revealed by the diffuse scattering originates from anomalies of energy of conduction electrons

Study on the Superlattices of Ternary Alloys by X-Ray

Studies on the superlattices of ternary alloys were recently developed, but only a new experimental results by X-ray have been reported. The ternary system of iron-aluminum-silicon, which contains the industrially important ferromagnetic alloy "Seudust" and has two superlattices of the same type on the iron-aluminum and iron-silicon sides, offers various interesting problems in connection with the superlattice theory. The present work was undertaken in this ternary system to confirm by X-ray a composition-range in which the superlattice of the 3 : 1 type can exist, because no work had yet been reported concerning it. The result showed that all ferromagnetic singularities were found in this composition-range