Finite element analysis on Titan STL3 OTR tires

Finite element tire modeling can be a challenging process, due to the overall complexities within the tire and the many variables that are required to produce capable predictive simulations. Utilizing tools from Abaqus finite element software, adequate predictive simulations that represent actual operational conditions can be made possible. Many variables that result from complex geometries and materials, multiple loading conditions, and surface contact can be incorporated into modeling simulations. This thesis outlines modeling practices used to conduct analysis on specific tire variants of the STL3 series OTR tire line, produced by Titan Tire. Finite element models were created to represent an inflated tire and rim assembly, supporting a 30,000 lb load while resting on a flat surface. Simulations were conducted with reinforcement belt cords at variable angles in order to understand how belt cord arrangement affects tire components and stiffness response.

A Preliminary Study of the Micro-Fauna of Certain Paleozoic Formations of Montana

The study of the micro-fauna of Montana formations has been almost entirely neglected. Because the petroleum industry of this state has not felt the necessity for using micro-paleontology in its sub-surface correlations, the science has been but little used. The Montana Power Company has had an examination made of some of its well cuttings by a competent micro-paleontologist who found some foraminifera in Mesozoic sediments. However, no investiga­tions have been made to determine the presence and character of the micro-fauna of the Paleozoic formations of Montana.

The Amplifier - v. 5, no. 3

In this issue...Student Union Building, International Club, Y.M.C.A., Student Wives Club, Orediggers, Continental Oil Company, "Who's Who", United States Army

Assessing the effectiveness of a long-standing rocky intertidal protected area and its contribution to the regional conservation of species, habitats and assemblages

1. The acceptance of reserves as a useful management strategy relies on evidence of their effectiveness in preserving stocks of harvested species and conserving biodiversity. A history of ad hoc decisions in terrestrial and marine protected area planning has meant that many of these areas are contributing inefficiently to conservation goals. The conservation value of existing protected areas should be assessed when planning the placement of additional areas in a reserve network. 2. This study tested (1) the effectiveness of protection for intertidal molluscs of a marine reserve (Bouddi Marine Extension, NSW, Australia) established in 1971, and (2) the contribution of the protected area to the conservation of regional species, assemblages, and habitats. 3. The shell length and population density of one harvested (Cellana tramoserica), and three non-harvested species (Bembicium nanum, Morula marginalba, Nerita atramentosa) of intertidal molluscs were examined in the protected area and two reference locations over two seasons. 4. The heavily collected limpet C. tramoserica was significantly larger in the protected area and was the only species to exhibit a significant difference. No species significantly differed in population density between the protected area and reference locations. 5. Temporally replicated surveys of macro-molluscs at 21 locations over 75km of coastline identified that the existing protected area included 50% of species, two of five assemblage types and 19 of 20 intertidal rocky shore habitats surveyed in the study region. Reservation of a further three rocky reefs would protect a large proportion of species (71%), a representative of each assemblage and all habitat types. 6. Despite originally being selected in the absence of information on regional biodiversity, the protected area is today an effective starting point for expansion to a regional network of intertidal protected areas.

Antagonizing Nogo-receptor 1 promotes the number of cultured dopaminergic neurons and elongates their neurites

The myelin-associated protein Nogo-A and its receptor Nogo-receptor 1 (NgR1) are known as potent growth inhibitors of the adult central nervous system (CNS). Nogo-A is mostly expressed on the surface of oligodendrocytes, but is also found in neurons of the adult and developing CNS. This observation suggests that Nogo-A serves additional functions in the brain. Hence, in the present study, we investigated the effects of antagonizing NgR1 on cultured organotypic and dissociated dopaminergic neurons. For that purpose ventral mesencephalic cultures from E14 rat embryos were grown in absence or presence of the NgR1 antagonist NEP1-40 for 1 week. Treatment with NEP1-40 significantly increased cell densities of tyrosine hydroxylase-immunoreactive neurons. Moreover, organotypic ventral mesencephalic cultures displayed a significantly bigger volume after NEP1-40 treatment. Morphological analysis of tyrosine hydroxylase-positive neurons disclosed longer neurites and higher numbers of primary neurites in dissociated cultures incubated with NEP1-40, whereas soma size was not changed. In conclusion, our findings demonstrate that interfering with Nogo-A signaling by antagonizing NgR1 modulates dopaminergic neuron properties during development. These observations highlight novel aspects of the role of Nogo-A in the CNS and might have an impact in the context of Parkinson's disease.

Streaming Video: Student Performance and Relative Use in the Preclinical Curriculum

Purpose: To assess the relationship between student utilization of learning resources, including streaming video (SV), and their performance in the pre-clinical curriculum. [See PDF for complete abstract]

Review: Reducing Adolescent Sexual Risk: A Theoretical Guide for Developing and Adapting Curriculum-Based Programs

A review of Reducing Adolescent Sexual Risk: A Theoretical Guide for Developing and Adapting Curriculum-Based Programs by Douglas Kirby.

Developmental Changes in the Structure and Composition of the Postsynaptic Density

The development of the brain and its underlying circuitry is dependent on the formation of trillions of chemical synapses, which are highly specialized contacts that regulate the flow of information from one neuron to the next. It is through these synaptic connections that neurons wire together into networks capable of performing specific tasks, and activity-dependent changes in their structural and physiological state is one way that the brain is thought to adapt and store information. At the ultrastructural level, developmental and activity-dependent changes in the size and shape of dendritic spines have been well documented, and it is widely believed that structural changes in spines are a hallmark sign of synapse maturation and alteration of synaptic physiology. While changes in spine structure have been studied extensively, changes in one of its most prominent components, the postsynaptic density (PSD), have largely evaded observation. The PSD is a protein-rich organelle on the cytoplasmic side of the postsynaptic membrane, where it sits in direct opposition to the presynaptic terminal. The PSD functions both to cluster neurotransmitter receptors at the cell surface as well as organize the intracellular signaling molecules responsible for transducing extracellular signals to the postsynaptic cell. Much is known about the chemical composition of the PSD, but the structural arrangement of its molecular components is not well documented. Adding to the difficulty of understanding such a complex mass of protein machinery is the fact that its protein composition is known to change in response to synaptic activity, meaning that its structure is plastic and no two PSDs are identical. Here, immuno-gold labeling and electron tomography of PSDs isolated throughout development was used to track changes in both the structure and molecular composition of the PSD. State-of-the-art cryo-electron tomography was used to study the fine structure of the PSD during development, and provides an unprecedented glimpse into its molecular architecture in an un-fixed, unstained and hydrated state. Through this analysis, large structural and compositional changes are apparent and suggest a model by which the PSD is first assembled as a mesh-like lattice of proteins that function as support for the later recruitment of various PSD components. Spatial analysis of the recruitment of proteins into the PSD demonstrated that its assembly has an underlying order.

Commentary on "Grandparents in Kinship Care: Help or Hindrance to Family Preservation"

Invited commentary on "Grandparents in Kinship Care: Help or Hindrance to Family Preservation."

Increasing Silicon Concentrations in Bohemian Forest Lakes

Long-term trends of dissolved silicon (Si) concentrations in five glacial lakes in the Bohemian Forest, Czech Republic, recovering from acidification show higher mobility of Si from the soil to surface waters despite lower atmospheric deposition of acids. Si increased by 0.95 to 1.95 mu mol yr(-1) (36 to 51%) from 1986-2004 and with increasing pH. A change in soil solution conditions because of a sharp decrease in acidic deposition has led to marked decline in Al mobility and to considerable decreases in dissolved Al, especially Al3+. The increase in Si may be related to: (1) unblocking of the inhibitory effect of dissolved Al on weathering of alummosilicates, (2) biogenic opal (phytoliths) dissolving faster, and/or (3) lower Si precipitation as secondary alummosilicates in soil. The change in Al speciation on the dissolution rate of biogenic silica is critical. A lack of change in Si at sites outside central Europe may be explained by small or no decline in mobility of dissolved Al. The effect of a long-term increase in temperature was probably minor.