Monitoring active volcanoes: The geochemical approach

The geochemical surveillance of an active volcano aims to recognize possible signals that are related to changes in volcanic activity. Indeed, as a consequence of the magma rising inside the volcanic "plumbing system" and/or the refilling with new batches of magma, the dissolved volatiles in the magma are progressively released as a function of their relative solubilities. When approaching the surface, these fluids that are discharged during magma degassing can interact with shallow aquifers and/or can be released along the main volcano-tectonic structures. Under these conditions, the following main degassing processes represent strategic sites to be monitored.The main purpose of this special volume is to collect papers that cover a wide range of topics in volcanic fluid geochemistry, which include geochemical characterization and geochemical monitoring of active volcanoes using different techniques and at different sites. Moreover, part of this volume has been dedicated to the new geochemistry tools

geochemistry and geophysics of active volcanic lakes an introduction

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Quinolizidines. XXVIII. Racemic and chiral syntheses of ochromianine, an indoloquinolizidine alkaloid from Neisosperma miana

A full account is given of the first racemic and chiral syntheses of 11-methoxydihydrocorynantheol [(-)-1], a candidate structure for the Neisosperma alkaloid ochromianine. Coupling of (±)-trans-6-ethoxy-3-ethyl-2,3,4,5-tetrahydro-4-pyridineacetic acid ethyl ester [(±)-6] with 2-chloro-1-(6-methoxy-1H-indol-3-yl)ethanone (4) in the presence of KBr produced the lactam ketone (±)-7,which was then converted into the lactam (±)-9 through the oxazolium salt (±)-8. Bischler-Napieralski cyclization of (±)-9 followed by catalytic hydrogenation gave the tetracyclic ester (±)-11. On reduction with LiAlH_4,(±)-11 yielded the racemic target (±)-1. A parallel synthetic route starting from (+)-6 and 4 afforded the chiral target (-)-1 via (+)-7,8,(+)-9,and (-)-11. Identity of synthetic (-)-1 with ochromianine unequivocally established the structure and absolute stereochemistry of this alkaloid

Activity of Rho-family GTPases during cell division as visualized with FRET-based probes

Rho-family GTPases regulate many cellular functions. To visualize the activity of Rho-family GTPases in living cells, we developed fluorescence resonance energy transfer (FRET)–based probes for Rac1 and Cdc42 previously (Itoh, R.E., K. Kurokawa, Y. Ohba, H. Yoshizaki, N. Mochizuki, and M. Matsuda. 2002. Mol. Cell. Biol. 22:6582–6591). Here, we added two types of probes for RhoA. One is to monitor the activity balance between guanine nucleotide exchange factors and GTPase-activating proteins, and another is to monitor the level of GTP-RhoA. Using these FRET probes, we imaged the activities of Rho-family GTPases during the cell division of HeLa cells. The activities of RhoA, Rac1, and Cdc42 were high at the plasma membrane in interphase, and decreased rapidly on entry into M phase. From after anaphase, the RhoA activity increased at the plasma membrane including cleavage furrow. Rac1 activity was suppressed at the spindle midzone and increased at the plasma membrane of polar sides after telophase. Cdc42 activity was suppressed at the plasma membrane and was high at the intracellular membrane compartments during cytokinesis. In conclusion, we could use the FRET-based probes to visualize the complex spatio-temporal regulation of Rho-family GTPases during cell division

Epithelium-poor Odontogenic Fibroma with an Unusual Progress

Odontogenic fibroma (OF) is a relatively rare benign tumor derived from odontogenic ectodermal mesenchymal tissue. It is divided into central (COF) or peripheral OF (POF) based on the affected area. Regarding its pathological features, OF can also be classified as epithelium-rich (WHO type) or epithelium-poor (simple type), depending on the amount of odontogenic epithelium in the tumor. There is limited information available about the latter type because of its low incidence. We report case of simple type COF apparently like POF. A 52- year-old Japanese male was suffering from tenderness at the right posterior maxilla during occlusion with his removable partial denture. The lesion was diagnosed as a simple type OF arising at the edentulous region around the right molar site of the maxilla. A tumor resection was performed, and there was no evidence of recurrence at his 18-month follow-up examination. In addition, we provide a review of the literature with the most up-to-date information about this lesion so that it can be diagnosed correctly