Changes in bone structure and metabolism during simulated weightlessness: Endocrine and dietary factors

The role of vitamin D, PTH and corticosterone in the skeletal alterations induced by simulated weightlessness was examined. The first objective was to determine if changes in the serum concentrations of Ca, P sub i, osteocalcin, 25-OH-D, 24,25(OH)2D or 1,25(OH)2D also occur following acute skeletal unloading. Animals were either suspended or pair fed for 2, 5, 7, 10, 12 and 15 days and the serum concentrations of Ca, P sub i, osteocalcin and the vitamin D metabolites measured. Bone histology was examined at day 5 after suspension. Acute skeletal unloading produced a transient hypercalcemia, a significant fall in serum osteocalcin and serum 1,25(OH)2D, a slight rise in serum 24,25(OH)2D, but did not affect the serum concentrations of P sub i or 25-OH-D. At the nadir in serum 1,25(OH)2D serum osteocalcin was reduced by 22%, osteoblast surface by 32% and longitudinal bone growth by 21%

The role of 1,25-dihydroxyvitamin D in the inhibition of bone formation induced by skeletal unloading

Skeletal unloading results in osteopenia. To examine the involvement of vitamin D in this process, the rear limbs of growing rats were unloaded and alterations in bone calcium and bone histology were related to changes in serum calcium (Ca), inorganic phosphorus (P sub i), 25-hydroxyvitamin D (25-OH-D), 24,25-dihydroxyvitamin D (24,25(OH)2D and 1,25-dihydroxyvitamin D (1,25(OH)2D. Acute skeletal unloading induced a transitory inhibition of Ca accumulation in unloaded bones. This was accompanied by a transitory rise in serum Ca, a 21% decrease in longitudinal bone growth (P 0.01), a 32% decrease in bone surface lined with osteoblasts (P .05), no change in bone surface lined with osteoclasts and a decrease in circulating (1,25(OH)2D. No significant changes in the serum concentrations of P sub i, 25-OH-D or 24,25(OH)2D were observed. After 2 weeks of unloading, bone Ca stabilized at approximately 70% of control and serum Ca and 1,25(OH)2D returned to control values. Maintenance of a constant serum 1,25(OH)2D concentration by chronic infusion of 1,25(OH)2D (Alza osmotic minipump) throughout the study period did not prevent the bone changes induced by acute unloading. These results suggest that acute skeletal unloading in the growing rat produces a transitory inhibition of bone formation which in turn produces a transitory hypercalcemia

A Reusable, Extensible Infrastructure for Augmented Field Trips

This paper describes a reusable pervasive information infrastructure developed as part of the Equator IRC, designed to allow the construction of literacy based eLearning activities on top of material created as part of a more traditional visitors system. The architecture of the system is described along with details of the creation of the curated material and the subsequent adaption of the system by local primary school teachers to create a literacy experiences. Results of the first trials of the system are presented with conclusions drawn and discussion of future directions

UbiComp in Opportunity Spaces: Challenges for Participatory Design

The rise of ubiquitous computing (UbiComp), where pervasive, wireless and disappearing technologies offer hitherto unavailable means of supporting activity, increasingly opens up ‘opportunity spaces’. These are spaces where there is no urgent problem to be solved, but much potential to augment and enhance practice in new ways. Based on our experience of co-designing novel user experiences for visitors to an English country estate, we discuss challenges for PD in such an opportunity space. Key amongst these are how to build a working relationship of value when there are no urgent requirements; how to understand and scope the space of opportunities; and how to leave users with new resources of value to them

The Literacy Fieldtrip: Using UbiComp to Support Children's Creative Writing

Fieldtrips, traditionally associated with science, history and geography teaching, have long been used to support children’s learning by allowing them to engage with environments first-hand. Recently, ubiquitous computing (UbiComp) has been used to enhance fieldtrips in these educational areas by augmenting environments with a range of instruments, devices and sensors. However, the sorts of interaction design that UbiComp makes possible have the potential not just to enhance the value of educational techniques in known application areas, but also to expand the application of those techniques into new areas of curriculum. We report on a UbiComp-supported fieldtrip to support creative writing, associated with the learning of literacy skills. We discuss how the fieldtrip, designed and run in the grounds of a historic English country house with Year 5 UK schoolchildren, engendered interactions which changed both the processes and products of creative writing, with benefits for both teachers and children

A persistent infrastructure for augmented field trips

This paper describes an approach to the provision of pervasive field trips where a persistent infrastructure is provided, upon which teachers can easily create novel pervasive experiences for children. The physical infrastructure is briefly described along with the underlying information infrastructure, which enables the tools for authoring the content and designing the orchestration of the experience to be placed in the hands of teachers. A literacy experience and initial trials of the system are discussed, conclusions drawn, and future directions outlined

A hyperthermophilic phage decoration protein suggests common evolutionary origin with Herpesvirus Triplex proteins and an anti-CRISPR protein [preprint]

Virus capsid proteins reproducibly self-assemble into regularly-shaped, stable shells that protect the viral genome from external environmental assaults, while maintaining the high internal pressure of the tightly packaged viral genome. To elucidate how capsids maintain stability under harsh conditions, we investigated the capsid components of a hyperthermophilic virus, phage P74-26. We determined the structure of a capsid protein gp87 and show that it has the same fold as trimeric decoration proteins that enhance the structural stability of capsids in many other phage, despite lacking significant sequence homology. We also find that gp87 is significantly more stable than its mesophilic homologs, reflecting the high temperature environment in which phage P74-26 thrives. Our analysis of the gp87 structure reveals that the core domain of the decoration protein is conserved in trimeric capsid components across numerous dsDNA viruses, including human pathogens such as Herpesviruses. Moreover, this core β-barrel domain is found in the anti-CRISPR protein AcrIIC1, which suggests a mechanism for the evolution of this broad spectrum Cas9 inhibitor. Our work illustrates the principles for increased stability of a thermophilic decoration protein, and extends the evolutionary reach of the core trimeric decoration protein fold