Chemical evolution: A solar system perspective

During the last three decades major advances were made in the understanding of the formation of carbon compounds in the universe and of the occurrence of processes of chemical evolution in the solar system and beyond. This was made possible by the development of new astronomical techniques and by the exploration of the solar system by means of properly instrumented spacecraft. Some of the major findings made as a result of these observations are summarized

Martian oxidation processes and selection of ancient sedimentary samples for bio-organic analysis

The results obtained by the Viking Missions concerning organic and biological analysis are summarized and it is indicated that these results do not preclude the existence in buried or protected regions of the planet, organic molecules or fossil life. The use of automated instruments is suggested for the analyses of samples obtained from certain regions of the planet, as a preliminary step before they are selected, retrieved, and returned to Earth for more complete analysis

On the origin and early evolution of biological catalysis and other studies on chemical evolution

One of the lines of research in molecular evolution which we have developed for the past three years is related to the experimental and theoretical study of the origin and early evolution of biological catalysis. In an attempt to understand the nature of the first peptidic catalysts and coenzymes, we have achieved the non-enzymatic synthesis of the coenzymes ADPG, GDPG, and CDP-ethanolamine, under conditions considered to have been prevalent on the primitive Earth. We have also accomplished the prebiotic synthesis of histidine, as well as histidyl-histidine, and we have measured the enhancing effects of this catalytic dipeptide on the dephosphorylation of deoxyribonucleotide monophosphates, the hydrolysis of oligo A, and the oligomerization 2', 3' cAMP. We reviewed and further developed the hypothesis that RNA preceded double stranded DNA molecules as a reservoir of cellular genetic information. This led us to undertake the study of extant RNA polymerases in an attempt to discover vestigial sequences preserved from early Archean times. In addition, we continued our studies of on the chemical evolution of organic compounds in the solar system and beyond

Gas Chromatograph-quadrupole Mass Spectrometric Analysis of Organic Compounds

Gas chromatography and mass spectrometry of acetonitrile, furan, pyrrole, paraffins, and other aromatic organic compounds of biological significanc

In situ organic analysis of the lunar surface

Gas chromatography-mass spectrometry system for analysis of organic compounds on moon and planetary surface

Diseno de una bomba centrifuga : analisis numerico y experimental

This paper describes the use of a rotating all mirror image derotator system in collaboration with Particle Image Velocimetry (PIV) to visualise and quantitatively examine the flow patterns between the blades of a centrifugal impeller. Velocity contours and vector maps of the relative flow field within a blade passage are presented for an impeller speed of 350 rpm and a flow rate of 510 l/h. The data are compared with the results of a computational fluid dynamics (CFD) model

Estudio numerico de las condiciones de estabilidad de estructuras bidimensionales bajo carga aerodinamica

An investigation on the stability conditions of the catenary wire system for a wide of wind relative direction is presented. The analysis was made with numerical methods by means of the Fluent software. The calculated lift forces were introduced in the equation of motion of the cylinders and stability conditions for the coupled system flow-structure were obtained

Intramolecular C-H oxidative addition to iridium(I) triggered by trimethyl phosphite in N,N′-diphosphanesilanediamine complexes

The reaction of [Ir(SiNP)(cod)][PF] ([1][PF]) and of IrCl(SiNP)(cod) (5) (SiNP = SiMe{N(4-CHCH)PPh}) with trimethyl phosphite affords the iridium(iii) derivatives of the formula [IrHCl(SiNP-H){P(OMe)}] (x = 0, 3; x = 1, 6) containing the κC,P,P′-coordinated SiNP-H ligand (SiNP-H = Si(CH)(CH){N(4-CHCH)PPh}). The thermally unstable pentacoordinated cation [Ir(SiNP){P(OMe)}(cod)] (2) has been detected as an intermediate of the reaction and has been fully characterised in solution. Also, the mechanism of the C-H oxidative addition has been elucidated by DFT calculations showing that the square planar iridium(i) complexes of the formula [IrCl(SiNP){P(OMe)}] (x = 0, 4; x = 1, 7) should be firstly obtained from 2 and finally should undergo the C-H oxidative addition to iridium(i) via a concerted intramolecular mechanism. The influence of the counterion of 2 on the outcome of the C-H oxidative addition reaction has also been investigated.Financial support from Spanish “Ministerio de Economía y Competitividad” (CTQ2013–42532–P), “Diputación General de Aragón” (Group E07) and University of Zaragoza (UZCUD2014–CIE–13) is gratefully acknowledged.Peer Reviewe

“Patch”ing Up Our Tumor Signaling Knowledge

The tumor suppressor Patched1 (Ptch1) possesses well-described roles in regulating sonic hedgehog (SHH) signaling in the skin and preventing the formation of basal cell carcinomas (BCCs). In this issue, Kang et al. extend their previous work to show that a naturally occurring allele of Ptch1 found in FVB mice promotes early squamous cell carcinoma (SCC) growth without aberrant activation of the SHH pathway. The study reveals new roles for Ptch1 that lie at the nexus between BCC and SCC formation