Estimation of hourly average solar radiation on tilted surface via ANNs

An innovative approach is proposed for the estimation of hourly average solar radiation on tilted surface. The proposed approach, which is based on artificial neural networks and problem decomposition, demonstrates the following characteristics: Accuracy. Superior estimation is attained over both conventional approaches and theoretical models. Simplicity and efficiency. A small training set is employed and the training/test patterns involve few easily obtainable parameters. Generalization capability and robustness to noise. Apart from being of interest in meteorology, the accurate and efficient estimation of hourly average solar radiation on tilted surface is especially important in solar energy applications.     

Regulation of Hex gene expression by a Smads-dependent signaling pathway

The homeobox gene Hex is expressed in multiple cell types during embryogenesis and is required for liver and monocyte development. Hex is expressed in the foregut region of late gastrula avian and mammalian embryos in a pattern that overlaps with expression of bone morphogenetic proteins (BMPs). Here we investigate the relationship between BMP signaling and Hex gene expression. We find that Hex expression in avian anterior lateral endoderm is regulated by autocrine BMP signaling. Characterization of the mouse Hex gene promoter identified a 71-nucleotide BMP-responsive element (BRE) that is required for up-regulation of Hex by an activated BMP signaling pathway. The Hex BRE binds Smad4 and Smad1-Smad4 complexes in vitro, and in transfection assays, it is responsive to Smad1 and Smad4 but not to Smad2 and Smad4 or Smad3 and Smad4. The BRE contains two copies of a GCCGnCGC-like motif that in Drosophila is the binding site for Mad and Madea followed by two CAGAG boxes that are similar to sequences required for transforming growth factor-beta/activin responsiveness of several vertebrate genes. Mutation of the GC elements, but not the two CAGAG boxes, abolishes Smads responsiveness in the intact Hex promoter, whereas mutations in both the GC elements and CAGAG boxes show that they act cooperatively to confer Smads responsiveness to the Hex promoter. The Hex BRE can confer Smads responsiveness to a heterologous promoter, and in this context, both the GC-rich elements and the CAGAG boxes are required for Smads-dependent promoter activity. An element almost identical to the Hex BRE is present within the BMP-responsive Nkx2-5 gene promoter, suggesting that the Hex BRE represents a common response element for genes regulated by BMP signaling in the foregut region of the embryo.     

Evaluation of Tat-encoding bicistronic human immunodeficiency virus type 1 gene transfer vectors in primary canine bone marrow mononuclear cells

Tat-encoding human immunodeficiency virus type 1 (HIV-1) gene transfer vectors were evaluated in primary canine bone marrow mononuclear cells. Tat vectors provided higher levels of gene expression than vectors with internal promoters. The HIV-1 vector was also more efficient than Moloney murine leukemia virus (MoMLV) vectors for transduction of canine bone marrow mononuclear cells in vitro. Transplantation experiments in dogs with transduced autologous marrow cells confirmed the superiority of HIV-1 vectors over MoMLV vectors for gene transfer into canine bone marrow cells. Tat vectors may be useful not only for providing high levels of therapeutic gene expression in hematopoietic cells but also for study of the biological effects of Tat in those tissues in the canine model.     

Y-chromosomal DNA variation in Pakistan

Eighteen binary polymorphisms and 16 multiallelic, short-tandem-repeat (STR) loci from the nonrecombining portion of the human Y chromosome were typed in 718 male subjects belonging to 12 ethnic groups of Pakistan. These identified 11 stable haplogroups and 503 combination binary marker/STR haplotypes. Haplogroup frequencies were generally similar to those in neighboring geographical areas, and the Pakistani populations speaking a language isolate (the Burushos), a Dravidian language (the Brahui), or a Sino-Tibetan language (the Balti) resembled the Indo-European-speaking majority. Nevertheless, median-joining networks of haplotypes revealed considerable substructuring of Y variation within Pakistan, with many populations showing distinct clusters of haplotypes. These patterns can be accounted for by a common pool of Y lineages, with substantial isolation between populations and drift in the smaller ones. Few comparative genetic or historical data are available for most populations, but the results can be compared with oral traditions about origins. The Y data support the well-established origin of the Parsis in Iran, the suggested descent of the Hazaras from Genghis Khan's army, and the origin of the Negroid Makrani in Africa, but do not support traditions of Tibetan, Syrian, Greek, or Jewish origins for other populations.     

Disruption of msl3 abolishes the synthesis of mycolipanoic and mycolipenic acids required for polyacyltrehalose synthesis in Mycobacterium tuberculosis H37Rv and causes cell aggregation

Cell wall lipids of Mycobacterium tuberculosis containing multiple methylbranched fatty acids play critical roles in pathogenesis and thus offer targets for new antimycobacterial drugs. Mycocerosicacid synthase gene (mas) encodes the enzyme that produces one class of such acids. Seven mas-like genes (msls) were identified in the genome. One of them, msl3, originally annotated as two separate genes, pks 3 and pks 4, is now shown to constitute a single open reading frame, which encodes a 220.3 kDa protein. Msl3 was disrupted using a phage mediated delivery system and the gene replacement in the mutant was confirmed by polymerase chain reaction analysis of the flanking regions of the introduced disrupted gene and by Southern analysis. Biochemical analysis showed that the msl3 mutant does not produce mycolipanoic acids and mycolipenic(phthienoic) acids, the major constituents of polyacyl trehaloses and thus lacks this cell wall lipid, but synthesizes all of the other classes of lipids. The absence of the major acyl chains that anchor the surface-exposed acyltrehaloses causes a novel growth morphology; the cells stick to each other, most probably via the intercellular interaction between the exposed hydrophobic cell surfaces, manifesting a bead-like growth morphology without affecting the overall growth rate.