Release of organic compounds from some Antarctic CI and CM chondrites by laboratory heating

Thermal release of organic compounds from three CI chondrites (Belgica (B)-7904,Yamato (Y)-82162,and Y-86720) and three CM chondrites (Y-74662,Y-791198,and Y-793321) was examined by DTA/TG-MS analysis. For identification of the compounds released, Y-791198 was also examined by DTA/TG-GC/MS analysis. The relative amounts of organic compounds released from these chondrites are, Y-74662≃Y-791198>Y-82162>Y-793321≃B-7094>Y-86720 The compounds released are aliphatic and aromatic hydrocarbons and N-, S-, and O-containing compounds. Of these, benzene and thiophene are the most abundant. Release patterns of some representative compounds were obtained along a programmed temperature profile from room temperature to 800℃. These patterns fall under one of two kinds; in one the release starts around 250℃ and continues to 700℃, and in the other release starts at 100℃ or 150℃ and ends at 300℃. The kinds and amounts of the organic compounds released are roughly related to the extent of the alteration and/or metamorphism of the chondrites as determined by mineralogical and petrographic studies

Tetra- and pentacyclic alkanes in the Cretaceous/Tertiary boundary sediments at Kawaruppu, Hokkaido, Japan

Twenty two steranes and 17 triterpanes were detected in the Cretaceous-Tertiary (K/T) boundary sediments at Kawaruppu, Hokkaido, Japan. These steranes and triterpanes were detected at a concentration level of 0.001-0.1nmol g-1. Their concentrations were smaller within the K/T boundary claystone than in the sediments above and below the claystone, which are likely related to the large biomass extinction event at the end of the Cretaceous. The concentrations of 5α-cholestane and the relative ones of 17α,21β-hopane in the sediments above the boundary claystone were about a half of those in the sediments below the claystone, whereas those of 5α-ergostane, 5α-stigmastane, and oleanane in the sediments above were less than a half abundance level of those in the sediments below the claystone. Diastereomer ratios of steranes and triterpanes were nearly constant over the sediments. No tricyclic alkanes were detected in the sediments.This work was supported by the Grant-in-Aid for ScientificResearch (B) No.11440166 from the Ministry of Education, Science, Sports and Culture, Japan and the Research Grant for Fellowship No.00007064 to H. Y. from Japanese Society for the Promotion of Science

A Case of Choroidal Neovascularization Secondary to Unilateral Retinal Pigment Epithelium Dysgenesis

Aim: To report a case of choroidal neovascularization secondary to unilateral retinal pigment epithelium dysgenesis (URPED), which was resistant to posterior subtenon injection of triamcinolone acetonide (STTA) and intravitreal bevacizumab injection (IVB). Case Report: An 8-year-old boy was referred to us because of a unilateral unique clinical appearance on funduscopic examination in his left eye (OS). A geometric lesion at the retinal pigment epithelium level of the interpapillomacular area was disclosed OS. The optic nerve was slightly hyperemic OS. Findings from the right fundus examination were normal. Based on these characteristic findings, he was diagnosed as having URPED. Best corrected Landolt ring chart visual acuity (BCVA) was 1.0 in both eyes. Twenty-three months after the first visit, the patient presented with visual disturbance OS. Funduscopic examination showed an expansion of the geometric lesion and the development of a subfoveal choroidal neovascularization (CNV). BCVA was 0.4 OS. Two-time STTA (40 mg/1 ml) was performed at the onset of CNV and 6 months later, and additional IVB (1.25 mg/0.05 ml) was done 10 months later for the treatment of CNV, but the geometric lesion and CNV were resistant to the treatment and continued to expand. Seven years after the first visit, the geometric lesion and the CNV kept expanding steadily. Conclusion: URPED is a rare clinical entity, and the prognosis of this disease is still unclear. The visual prognosis may depend on whether CNV fully develops