Decadal–centennial-scale solar-linked climate variations and millennial-scale internal oscillations during the Early Cretaceous

Understanding climate variability and stability under extremely warm ‘greenhouse’ conditions in the past is essential for future climate predictions. However, information on millennial-scale (and shorter) climate variability during such periods is scarce, owing to a lack of suitable high-resolution, deep-time archives. Here we present a continuous record of decadal- to orbital-scale continental climate variability from annually laminated lacustrine deposits formed during the late Early Cretaceous (123–120 Ma: late Barremian–early Aptian) in southeastern Mongolia. Inter-annual changes in lake algal productivity for a 1091-year interval reveal a pronounced solar influence on decadal- to centennial-scale climatic variations (including the ~ 11-year Schwabe cycle). Decadally-resolved Ca/Ti ratios (proxy for evaporation/precipitation changes) for a ~ 355-kyr long interval further indicate millennial-scale (~ 1000–2000-yr) extreme drought events in inner-continental areas of mid-latitude palaeo-Asia during the Cretaceous. Millennial-scale oscillations in Ca/Ti ratio show distinct amplitude modulation (AM) induced by the precession, obliquity and short eccentricity cycles. Similar millennial-scale AM by Milankovitch cycle band was also previously observed in the abrupt climatic oscillations (known as Dansgaard–Oeschger events) in the ‘intermediate glacial’ state of the late Pleistocene, and in their potential analogues in the Jurassic ‘greenhouse’. Our findings indicate that external solar activity forcing was effective on decadal–centennial timescales, whilst the millennial-scale variations were likely amplified by internal process such as changes in deep-water formation strength, even during the Cretaceous ‘greenhouse’ period

抗ラット肺クララ細胞分泌物質抗体の作製

ラットの肺洗浄液内蛋白を抗原としてウサギを免疫した.吸収操作を行って得られた抗体を使って,ホルマリン固定・パラフィン包埋されたラットの肺組織を酵素抗体法で免疫組織化学的に検索すると,形態的にクララ細胞と思われる細胞に特異的な反応を示していた.B-5固定材料ではクララ細胞のほかに細気管支上皮上のmucus blanketにも反応物質が存在した.プロテインA・ゴールドを用い電顕レベルで反応物質の局在を調べるとクララ細胞内の高電子密度の分泌顆粒に集中していた.これらの所見は抗原がクララ細胞と考えられる細胞で産生され,末梢気道に分泌されていることを示唆している.また,この抗体はラットのほかにはマウスのクララ細胞と交差反応を示したが,他の種(ハムスター,モルモット,ウサギ,犬,猫,猿,人)のそれとは反応しなかった.本報告では本抗体の作製方法について詳述した.By immunizing rabbits with the proteins in the rat lung lavage fluid, we have succeeded in producing antibodies against secretory products of the rat Clara cells. Immunohistochemically, these antibodies were demonstrated to specifically react with secretory products in the mucus blanket as well as Clara cells in B-5 fixed materials, and only with the latter in formalin-fixed materials. Immuno-electron-microscopic study using protein・A-gold showed that the reaction products were accumulated in the electron dense granules of the Clara cells. These findings were considered to indicate that antigens we used were indeed produced in the Clara cells and were secreted into the airway. The antibodies were also reacted with those of the mice, but not with hamsters, guinea pigs, rabbits, dogs, cats, monkeys or the human. In this communication, our preparatory method of producing antibodies is described in detail

Radiological differences in computed tomography findings and texture analysis between cystic lymph node metastases of human papillomavirus-positive oropharyngeal cancer and second branchial cysts

Purpose: The study aimed to analyse radiological differences in computed tomography (CT) findings and texture analysis between cystic lymph node metastases (CNM) in human papillomavirus (HPV)-positive oropharyngeal cancer (OPC) and second branchial cleft cysts (2nd BC). Material and methods: Patients with pathological evidence of CNM-HPV-OPC and 2nd BC, who underwent contrastenhanced CT, were retrospectively evaluated. The evaluated characteristics include age, sex, and CT findings. CT findings included the maximum and minimum transverse diameters, maximum caudal diameter, thickness of the peripheral wall, presence of internal septation, presence of surrounding fat stranding, location, and 40 texture parameters. Results: A total of 13 patients had CNM-HPV-OPC (19 lesions), while 20 patients had 2nd BC (20 lesions). Patients with 2nd BC were significantly younger than those with CNM-HPV-OPC (p < 0.001). In terms of diameter, 2nd BC lesions were significantly larger than the CNM-HPV-OPC lesions (p < 0.001). CNM-HPV OPC lesions had significantly thicker walls than 2nd BC lesions (p < 0.001). CNM-HPV-OPC lesions had significantly higher association with internal septations than 2nd BC lesions (p < 0.001). Second BC lesions were significantly less common at level III than CNM-HPV-OPC lesions (p = 0.047). Among the 40 texture parameters measured, 8 had significant differences (p ≤ 0.001). Conclusions: There were significant differences in CT findings and textural parameters between CNM-HPV-OPC and 2nd BC lesions. These results may help in differentiating one from the other

Biogenically induced bedded chert formation in the alkaline palaeo-lake of the Green River Formation

Rhythmically bedded cherts are observed in both pelagic marine and lacustrine deposits, but the formation mechanism in the latter remains highly uncertain. Our study of alternating chert–dolomite beds in the Eocene Green River Formation, Utah, USA reveals dense accumulations of organic-matter spheres (30–50 μm diameter) of probable algal cyst origin in the chert layers, and centennial- to millennial-scale periodicities in chert layer deposition. A positive correlation between the degree of degradation of the organic spheres and Si distribution implies decomposition of algal organic matter lead to precipitation of lacustrine chert. As both alkalinity and dissolved silica were likely high in the palaeo-lake waters of the Green River Formation, we hypothesize that decomposition of algal organic matter lowered the pH of sediment pore waters and caused silica precipitation. We propose a formation model in which the initial abundance of algal organic matter in sediment varies with productivity at the lake surface, and the decomposition of this algal matter controls the extent of silica precipitation in sediment. The formation of rhythmically bedded chert–dolomite may be linked to centennial- to millennial-scale climatic/environmental factors that modulate algal productivity, which are possibly tied to solar activity cycles known to have similar periodicities

Does Vertebroplasty Affect Radiation Dose Distribution?: Comparison of Spatial Dose Distributions in a Cement-Injected Vertebra as Calculated by Treatment Planning System and Actual Spatial Dose Distribution

Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS) and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution