Measuring the Strain Field Gradients on the Surface of a Model Human Skull while Axially Loaded to Simulate Head-loading

Head-loading is a means of transporting heavy loads accross rough, rural terrains practiced by many peoples in Third World countries. Years of practicing head-loading is said to result in increase spinal bone density and permantly grooved skulls. The most infamous people who practice head-loading are the porters of Nepal, who carry loads by means of a head sling straped across their foreheads, and South African women, who carry loads directly on their heads. To simulate and measure the instantaneous micro deformations occurring on the surface of the skull due to head-loading, a test procedure has been developed using a plastic human skull model. The effect of applying an axial load to the skull is examined using a non-contact strain deformation measuring technique known as speckle image photogrammetry. This technique uses two high resolution cameras to monitor the three dimensional deformations occurring on the outer surface of a relatively large portion of the skull. ARAMIS optical deformation software (GOM Optical Measuring Techniques) has been used to compute the strain field gradients on the surface of the model plastic skull while loaded, suggesting a similar test procedure and speckling technique can be used on a masecrated human skull

Molecular Biology: Power Sequencing

Advances in DNA-sequencing technology provide unprecedented insight into the entire collection of four genomes\u27 transcribed sequences; they herald a new era in the study of gene regulation and genome function

Genome-wide Analysis of Drosophila Circular RNAs Reveals Their Structural and Sequence Properties and Age-Dependent Neural Accumulation

Circularization was recently recognized to broadly expand transcriptome complexity. Here, we exploit massive Drosophila total RNA-sequencing data, \u3e5 billion paired-end reads from \u3e100 libraries covering diverse developmental stages, tissues, and cultured cells, to rigorously annotate \u3e2,500 fruit fly circular RNAs. These mostly derive from back-splicing of protein-coding genes and lack poly(A) tails, and the circularization of hundreds of genes is conserved across multiple Drosophila species. We elucidate structural and sequence properties of Drosophila circular RNAs, which exhibit commonalities and distinctions from mammalian circles. Notably, Drosophila circular RNAs harbor \u3e1,000 well-conserved canonical miRNA seed matches, especially within coding regions, and coding conserved miRNA sites reside preferentially within circularized exons. Finally, we analyze the developmental and tissue specificity of circular RNAs and note their preferred derivation from neural genes and enhanced accumulation in neural tissues. Interestingly, circular isoforms increase substantially relative to linear isoforms during CNS aging and constitute an aging biomarker

The splicing regulators Tra and Tra2 are unusually potent activators of pre-mRNA splicing

Sexual differentiation in Drosophila is regulated through alternative splicing of doublesex. Female-specific splicing is activated through the activity of splicing enhancer complexes assembled on multiple repeat elements. Each of these repeats serves as a binding platform for the cooperative assembly of a heterotrimeric complex consisting of the SR proteins Tra, Tra2 and 9G8. Using quantitative kinetic analyses, we demonstrate that each component of the enhancer complex is capable of recruiting the spliceosome. Surprisingly, Tra, Tra2 and 9G8 are much stronger splicing activators than other SR protein family members and their activation potential is significantly higher than expected from their serine/arginine content. 9G8 activates splicing not only through its RS domains but also through its RNA-binding domain. The RS domains of Tra and Tra2 are required but not sufficient for efficient complex assembly. Thus, the regulated assembly of the dsx enhancer complexes leads to the generation of an extended activation domain to guarantee the ‘all or none’ splicing switch that is required during Drosophila sexual differentiation

Seasonal plumage condition variation and the thermal value of the feather coats of house sparrows (Passer domesticus)

Feathers are critical to how birds thermoregulate, and thus their total energy balance. The feather coat insulates birds by trapping air next to the skin and acting as a physical barrier to heat loss. Despite previous work studying thermal balance in birds, relatively few studies have focused on the thermal contribution of the feather coat alone; most studies have focused on physiological and behavioral responses. Moreover, to our knowledge, no studies have directly measured the effect of feather wear through the annual cycle on the thermal performance of the feather coat. To address this, we used a thermal camera to measure the temperature at the surface of the feather coat of live house sparrows (Passer domesticus) in winter (post-molt, unworn feathers) and summer (pre-molt, worn feathers), as well as flat-skins of the same specimens in order to isolate the thermal effect of the feather coat alone. We predicted that worn feather coats would lose more heat than unworn feather coats in both live birds and flat skins. Surprisingly, we found that feather wear had no effect on the thermal performance of the feather coat across seasons. The thermal balance of birds will be better understood when the thermal contribution of the feather coat is directly measured across more species and conditions