CHANGES IN ACCELERATION PHASE SPRINT BtOMECHANlCS WITH LOWER BODY WEARABLE RESISTANCE

Wearable resistance (WR) attached to the lower body may be advantageous for sprint acceleration training. The aim of this study was to quantify the kinematic and kinetic changes that occur during the sprint acceleration phase when lower body WR is worn. Radar and Optojump were used to assess fifteen male rugby athletes sprinting over 20 m under three different loading conditions: 0%, 3% and 5% body mass added weight (AW) attached to the lower body. Moderately loaded WR (3% AW) resulted in higher horizontal force and horizontal power outputs compared to heavier loading during the acceleration phase. Sprint acceleration biomechanics were minimally affected by WR loading up to 5% AW

Patient reactions to a web-based cardiovascular risk calculator in type 2 diabetes: a qualitative study in primary care.

Use of risk calculators for specific diseases is increasing, with an underlying assumption that they promote risk reduction as users become better informed and motivated to take preventive action. Empirical data to support this are, however, sparse and contradictory

Exact, Approximate, and Online Algorithms for Optimization Problems Arising in DVD Assignment

Zip.ca is an online DVD rental company that faces two major operational problems: calculation of the assignment of DVDs to customers every thirty minutes throughout the day and purchasing of new inventory in regular intervals. In this thesis, we model these two problems and develop algorithms to solve them. In doing so, we encounter many theoretical problems that are both applicable to Zip’s operations and intrinsically interesting problems independent of the application. First, we note that the assignment problem facing Zip is inherently in an online setting. With returns of DVDs being processed throughout the day, the dataset is constantly changing. Although the ideal solution would be to wait until the end of the day to make decisions, physical work load capacities prevent this. For this reason we discuss two online problems, online 0-1 budgeted matching and the budgeted Adwords auction. We present a 1/(2 w_max/w_min)-competitive algorithm for the online 0-1 budgeted matching problem, and prove that this is the best possible competitive ratio possible for a wide class of algorithms. We also give a (1− (S+1)/(S+e) )-competitive algorithm for the budgeted Adwords auction as the size of the bids and cost get small compared to the budgets, where S is the ratio of the highest and lowest ratios of bids to costs. We suggest a linear programming approach to solve Zip’s assignment problem. We develop an integer program that models the B-matching instance with additional constraints of concern to Zip, and prove that this integer program belongs to a larger class of integer programs that has totally unimodular constraint matrices. Thus, the assignment problem can be solved to optimality every thirty minutes. We additionally create a test environment to check daily performance, and provide real-time implementation results, showing a marked improvement over Zip’s old algorithm. We show that Zip’s purchasing problem can be modeled by the matching augmentation problem defined as follows. Given a graph with vertex capacities and costs, edge weights, and budget C, find a purchasing of additional node capacity of cost at most C that admits a B-matching of maximum weight. We give a PTAS for this problem, and then present a special case that is polynomial time solvable that still models Zip’s purchasing problem, under the assumption of uniform costs. We then extend the augmentation idea to matroids and present matroid augmentation, matroid knapsack, and matroid intersection knapsack, three NP-hard problems. We give an FPTAS for matroid knapsack by dynamic programming, PTASes for the other two, and demonstrate applications of these problems

AKT-independent PI3-K signaling in cancer - emerging role for SGK3

The phosphoinositide 3-kinase (PI3-K) signaling pathway plays an important role in a wide variety of fundamental cellular processes, largely mediated via protein kinase B/v-akt murine thymoma viral oncogene homolog (PKB/AKT) signaling. Given the crucial role of PI3-K/AKT signaling in regulating processes such as cell growth, proliferation, and survival, it is not surprising that components of this pathway are frequently dysregulated in cancer, making the AKT kinase family members important therapeutic targets. The large number of clinical trials currently evaluating PI3-K pathway inhibitors as a therapeutic strategy further emphasizes this. The serum- and glucocorticoid-inducible protein kinase (SGK) family is made up of three isoforms, SGK1, 2, and 3, that are PI3-K-dependent, serine/threonine kinases, with similar substrate specificity to AKT. Consequently, the SGK family also regulates similar cell processes to the AKT kinases, including cell proliferation and survival. Importantly, there is emerging evidence demonstrating that SGK3 plays a critical role in AKT-independent oncogenic signaling. This review will focus on the role of SGK3 as a key effector of AKT-independent PI3-K oncogenic signaling

Genetic Taster Status as a Mediator of Neural Activity and Swallowing Mechanics in Healthy Adults

As part of a larger study examining relationships between taste properties and swallowing, we assessed the influence of genetic taster status (GTS) on measures of brain activity and swallowing physiology during taste stimulation in healthy men and women. Twenty-one participants underwent videofluoroscopic swallowing study (VFSS) and functional magnetic resonance imaging (fMRI) during trials of high-intensity taste stimuli. The precisely formulated mixtures included sour, sweet-sour, lemon, and orange taste profiles and unflavored controls. Swallowing physiology was characterized via computational analysis of swallowing mechanics plus other kinematic and temporal measures, all extracted from VFSS recordings. Whole-brain analysis of fMRI data assessed blood oxygen responses to neural activity associated with taste stimulation. Swallowing morphometry, kinematics, temporal measures, and neuroimaging analysis revealed differential responses by GTS. Supertasters exhibited increased amplitude of most pharyngeal movements, and decreased activity in the primary somatosensory cortex compared to nontasters and midtasters. These preliminary findings suggest baseline differences in swallowing physiology and the associated neural underpinnings associated with GTS. Given the potential implications for dysphagia risk and recovery patterns, GTS should be included as a relevant variable in future research regarding swallowing function and dysfunction

Trophic roles of tadpoles in tropical Australian streams

Tadpoles can be abundant consumers in stream ecosystems, and may influence the structure and function of streams through their feeding activities and interactions with other organisms. To understand the contribution of tadpoles to stream functioning, and the potential impact of their loss, it is necessary to determine their diets and how they might influence food-web structure. Using gut-content analysis and stable-isotope analysis of N and C, we determined the main food sources and trophic positions of tadpoles of five native frog species, invertebrates, and fish in upland and lowland Australian Wet Tropics streams. Omnivory was prevalent among the tadpoles and invertebrates. Tadpoles consumed different food according to availability and nutrient quality, but assimilated mainly biofilm and algae. Most tadpoles and invertebrates assimilated the same high-quality foods. Food webs in upland riffles were simplified by local extinction of tadpoles, and were probably simplified in pools in the cooler months by seasonal decline in tadpole abundance. Food-web complexity was increased in some pools by the presence of predatory fish and a greater number of basal sources. As tadpoles are important seasonal components in stream food webs, their local extinction can greatly alter food-web structure and complexity and, possibly, processes such as leaf litter breakdown and sediment accumulation

The Imprinted Retrotransposon-Like Gene PEG11 (RTL1) Is Expressed as a Full-Length Protein in Skeletal Muscle from Callipyge Sheep

peer-reviewedMembers of the Ty3-Gypsy retrotransposon family are rare in mammalian genomes despite their abundance in invertebrates and some vertebrates. These elements contain a gag-pol-like structure characteristic of retroviruses but have lost their ability to retrotranspose into the mammalian genome and are thought to be inactive relics of ancient retrotransposition events. One of these retrotransposon-like elements, PEG11 (also called RTL1) is located at the distal end of ovine chromosome 18 within an imprinted gene cluster that is highly conserved in placental mammals. The region contains several conserved imprinted genes including BEGAIN, DLK1, DAT, GTL2 (MEG3), PEG11 (RTL1), PEG11as, MEG8, MIRG and DIO3. An intergenic point mutation between DLK1 and GTL2 causes muscle hypertrophy in callipyge sheep and is associated with large changes in expression of the genes linked in cis between DLK1 and MEG8. It has been suggested that over-expression of DLK1 is the effector of the callipyge phenotype; however, PEG11 gene expression is also strongly correlated with the emergence of the muscling phenotype as a function of genotype, muscle type and developmental stage. To date, there has been no direct evidence that PEG11 encodes a protein, especially as its anti-sense transcript (PEG11as) contains six miRNA that cause cleavage of the PEG11 transcript. Using immunological and mass spectrometry approaches we have directly identified the full-length PEG11 protein from postnatal nuclear preparations of callipyge skeletal muscle and conclude that its over-expression may be involved in inducing muscle hypertrophy. The developmental expression pattern of the PEG11 gene is consistent with the callipyge mutation causing recapitulation of the normal fetal-like gene expression program during postnatal development. Analysis of the PEG11 sequence indicates strong conservation of the regions encoding the antisense microRNA and in at least two cases these correspond with structural or functional domains of the protein suggesting co-evolution of the sense and antisense genes

Relative Expression Levels Rather Than Specific Activity Plays the Major Role in Determining In Vivo AKT Isoform Substrate Specificity

The AKT protooncogene mediates many cellular processes involved in normal development and disease states such as cancer. The three structurally similar isoforms: AKT1, AKT2, and AKT3 exhibit both functional redundancy and isoform-specific functions; however the basis for their differential signalling remains unclear. Here we show that in vitro, purified AKT3 is ∼47-fold more active than AKT1 at phosphorylating peptide and protein substrates. Despite these marked variations in specific activity between the individual isoforms, a comprehensive analysis of phosphorylation of validated AKT substrates indicated only subtle differences in signalling via individual isoforms in vivo. Therefore, we hypothesise, at least in this model system, that relative tissue/cellular abundance, rather than specific activity, plays the dominant role in determining AKT substrate specificity in situ