Cladistic analysis of the apolipoprotein AI-CIH-AIV gene cluster using a healthy French Canadian sample. I. Haploid analysis

A cladistic analysis was carried out to identify haplotypes hypothesized to differ for functional DNA sequence variations within the apolipoprotein (apo) AI-CIII-AIV gene cluster that affect plasma lipid, lipoprotein and apolipoprotein levels. A sample of unrelated healthy French Canadians was studied. First, a cladogram of the observed apo AI-CIII-AIV haplotypes was estimated. Then this cladogram was used to define a statistical analysis of the association between haplotype variation and variation in plasma lipid, lipoprotein and apolipoprotein levels. Three haplotypes were identified which were associated with small (5–12% of the total sum of squares) pleiotropic effects on plasma lipid, lipoprotein and apolipoprotein traits and these effects were context, i.e. gender, dependent.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66070/1/j.1469-1809.1995.tb00742.x.pd

Solar pond powered liquid desiccant evaporative cooling

Liquid desiccant cooling systems (LDCS) are energy efficient means of providing cooling, especially when powered by low-grade thermal sources. In this paper, the underlying principles of operation of desiccant cooling systems are examined, and the main components (dehumidifier, evaporative cooler and regenerator) of the LDCS are reviewed. The evaporative cooler can take the form of direct, indirect or semi-indirect. Relative to the direct type, the indirect type is generally less effective. Nonetheless, a certain variant of the indirect type - namely dew-point evaporative cooler - is found to be the most effective amongst all. The dehumidifier and the regenerator can be of the same type of equipment: packed tower and falling film are popular choices, especially when fitted with an internal heat exchanger. The energy requirement of the regenerator can be supplied from solar thermal collectors, of which a solar pond is an interesting option especially when a large scale or storage capability is desired

Synchronous age progressive hotspot trails on the African Superswell

Establishing if and when South Atlantic hotspots interacted with surface processes during rifting and continental breakup is important for understanding the mechanisms that control the evolution of passive margins and their adjacent continents. One approach is to reconstruct the volcanic history of hotspot trails located on the African Superswell in order to find the locations of hotspots during rifting and breakup to determine if, for example, they caused extreme fluxes of magma and post-rift uplift along the continental margin. However, because hotspot trails located south of the classical Tristan-Gough are virtually un-sampled we don’t know how many hotspots might have existed or for how long, and whether they originated from the core-mantle boundary or much shallower depths. In 2006 we dredge sampled hotspot trails located on the African Superswell using the RV Polarstern, an icebreaker capable of working in the poor weather conditions in the Southern Ocean. Combining new and existing Ar/Ar isotopic ages shows that volcanism migrated synchronously along co-parallel hotspot trails consistent with northeastern African plate motion relative to the leading edges of the African Superswell and an underlying stable Superplume (large low-shear-velocity province) extending from the core-mantle boundary. Between roughly 132 and 100 million years ago only the Tristan-Gough hotspot trail developed where rifting and breakup facilitated the rise of hotspot melts to the surface, while along rest of the leading edge hotspot volcanism was suppressed by the African continent. Such a notion implies that the African passive continental margin was migrating relative to the leading edge of the African Superplume for as long as 30 million years after continental rifting and breakup had facilitated the 132 Ma Parana-Etendeka continental flood basalts and initiation of the Tristan-Gough hotspot trail. This provides a mechanism for extended late stage interplay between deep mantle processes and the passive margin and adjacent continents that might explain extensive magmatism, lithospheric thinning and phases of postrift uplift

Human COL6A1: Genomic characterization of the globular domains, structural and evolutionary comparison with COL6A2

The αl(VI) and a2(VI) chains of type VI collagen (nonfibrillar) are highly similar and are encoded by single-copy genes in close proximity on human Chromosome (Chr) 21q22.3, a gene-rich region that has proved refractory to cloning. For the αl(VI) chain, only the regions encoding the triple-helical and the promoter have been characterized hitherto. To facilitate our study of the role of this gene in the phenotype of Down syndrome, we have cloned and sequenced the amino- and carboxyl-terminal globular domains of COL6A1. The amino-terminal domain consists of seven exons and the carboxyl-terminal globular domain of nine exons. Together with the exons of the triple-helical domain, COL6A1 is encoded by a total of 36 exons spanning approximately 30 kb. Comparison of the genomic organization of COL6A1 and COL6A2 revealed that despite the similarity within their triple-helical domains, the intron-exon structures of their globular domains differ markedly. Conservation is limited to the exons encoding amino acids immediately adjacent to the triple-helical region, including the cysteine residues essential for the structure of mature collagen VI. The intron-exon structures of these two genes are highly similar to the collagen VI genes of chicken. These data suggest that COL6A1 and COL6A2 arose from a gene duplication before the divergence of the reptilian and mammalian lineages