INFLUENCE OF AGING ON THE DYNAMICS OF LATERAL STABILIZATION IN WALKING, IN DIFFERENT EXPERIHENTAL CONDITIONS RELATED TO SHOE WEARING AND FLOOR HARDNESS

Review of biomechanics literature on the influence of aging on the locomotor system indicates that safe load bearing as well as deformation sustaining capabilities of biological tissues decrease with age. Postural studies of older populations have di8closed more body sway than in younger age groups and have often associated loss of balance with locomotion problems of old age people. On the other hand, biomechanical studies of walking and running have already demonstrated t h a t wearing shoes and shoe characteristics can play an important r o l e in shock absorption. However the influence of aging on the dynamic of lateral stabilization in walking in relationship with shoe wearing and floor hardness has received very little attention. Such a biomechanical approach t o locomotion is becoming more important since more and more older people are involved in sport and fitness activities including some form of locomotion. The present study has been undertaken in order to investigate the influence of aging together with shoe wearing and floor hardness on some of the main components, of lateral stabilization in walking, namely the lateral forces, the lateral impulse and the lateral deviation o f the center of pressure. Three groups of 15 physically active male subjects (17-22, 40-45 and 65-70 years old) were instructed to walk on a tri-dimensional force platform a t a predetermined pace set with a metronome;. Experimental conditions included walking barefoot and with regular shoes, on a hard and a softer surfaces. Kinetic data were recorded on the 5th, 25th, 50th, 100th and 500th steps for each condition, with the use of the computerized . Ariel Performance Analysis System. Analysis of the results disclosed important differences between the age groups in all three experimental parameters. Lower lateral forces exerted by the older age group lead t o the hypothesis of a different stabilization strategy based on energy saving. Findings were also discussed in relationship with the lateral stabilization process and applications were made to sport and fitness activities a s well a s the daily living situations

Degradation of Chlorinated Hydrocarbons in Groundwater Passing Through the Treatment Wetland at Wright-Patterson Air Force Base: Analysis of Results Collected During 2001-\u2706

Constructed wetlands are an efficient and cost effective means for chlorinated aliphatic hydrocarbon remediation, and will therefore continue to gain momentum as an accepted treatment by the US EPA (U.S. EPA, 1995; Amarante, 2000; Lien, 2001; WETPOL, 2009). The treatment options for chlorinated aliphatic hydrocarbons (CAHs), including wetlands, capitalize on aerobic/anaerobic interfaces in which bacterially mediated reduction-oxidation reactions degrade pollutants (Li, 1997; Bradley, 1998; Lorah and Voytek, 2004; Amon, 2007; Imfeld, 2008). In August 2000, researchers at Wright State University (WSU) combined efforts with the United States Air Force Institute of Technology (AFIT) to construct a pilot-scale upward-flow treatment wetland on Wright-Patterson Air Force Base with parameters that could remediate perchloroethene (PCE) found in a nearby aquifer (Amon et al., 2007). Eleven studies of short duration have since documented the existance of anerobic and aerobic interfaces by measuring various terminal electron acceptors (sulfate, nitrate, methane, iron) and numerous other parameters. The studies evaluated PCE degradation rates, geochemical profiles, hydraulic conductivity and chlorinated ethene concentrations. (Bugg, 2002; Opperman, 2002; Clemmer, 2003; Kovacic, 2003; BonDurant, 2004; Sobolewski, 2004; Lach, 2004; Schlater, 2006; Mohamud, 2007; Waldron, 2007, Corbin, 2008). The present research has attempted to compile, organize, and re-analyze the data collected by AFIT and WSU researchers during 2001-2006. Data was analyzed using Jenks Optimization (goodness of variance fit) method to identify and remove outliers. Meta analysis of CAH concentrations and redox parameters was performed by creating data subsets of individual piezometer and depths, influent to effluent transect data and ArcGIS maps. The present analysis concludes that a fully functioning wetland with strongly reducing geochemical conditions and flow patterns capable of PCE destruction developed at this site within 18-24 months. Dechlorination of CAHs was observed at every depth and at 63 of 66 sampled locations despite significant differences in hydraulic conductivity and available electron acceptors. Rate of dechlorination varied with depth and hydraulic conductivity. Strongest reducing conditions developed at Middle layer (0.69 m) and demonstrated the highest rates of PCE dechlorination. Maximum degradation of vinyl chloride (VC) and 1,2 dichloroethenes (DCE) occurred in Upper layer (0.23m) where conditions may have been more oxidizing. The size of the pilot-scale treatment wetland generally allowed adequate residence time despite short circuits. However, two exceptions were observed: (i) near the effluent, increases in head pressure, due to laminar flow bring higher concentrations from gravel layer to surface quickly, and (ii) CAHs re transmitted quickly along the wetland\u27s outer boundary, possibly along the soil-PVC liner. Despite these effects, with the exception of one researcher\u27s results, the effluent concentrations for all CAH species remained below their respective MCLs after January 2003. The study suggests that the construction of wetland for the treatment PCE-contaminated groundwater include establishing and employing a grid monitoring system to ascertain geographical boundaries for problem areas, frequent sampling in initial 24 months and establishing controls on influent pumping system to adjust residence time as needed

A BIOMECHANICAL AND KINESIOLOGICAL APPROACH IN THE TEACHING OF EFFICIENT SURGICAL SKILLS TO MEDICAL STUDENTS

A competency-based surgery residents teaching and training program including a biomechanical and kinesiological approach was developed in order to improve procedural learning and mastery of invasive skills. Principles of biomechanics and kinesiology have been taught and applied to many aspects of surgical tasks, including instrument holding and manipulation, body positioning and posture, segments alignment. Results demonstrate more precise movements and more efficient performance of surgical tasks in residents participating in the program

Predation pressure by avian predators suggests summer limitation of small-mammal populations in the Canadian Arctic

Predation has been suggested to be especially important in simple food webs and less productive ecosystems such as the arctic tundra, but very few data are available to evaluate this hypothesis. We examined the hypothesis that avian predators could drive the population dynamics of two cyclic lemming species in the Canadian Arctic. A dense and diverse suite of predatory birds, including the Snowy Owl (Bubo scandiacus), the Rough-legged Hawk (Buteo lagopus), and the Long-tailed Jaeger (Stercorarius longicaudus), inhabits the arctic tundra and prey on collared (Dicrostonyx groenlandicus) and brown (Lemmus trimucronatus) lemmings during the snow-free period. We evaluated the predation pressure exerted by these predators by combining their numerical (variation in breeding and fledgling numbers) and functional (variation in diet and daily consumption rates) responses to variations in lemming densities over the 2004-2010 period. Breeding density and number of fledglings produced by the three main avian predators increased sharply without delay in response to increasing lemming densities. The proportion of collared lemmings in the diet of those predators was high at low lemming density (both species) but decreased as lemming density increased. However, we found little evidence that their daily consumption rates vary in relation to changes in lemming density. Total consumption rate by avian predators initially increased more rapidly for collared lemming but eventually leveled off at a much higher value for brown lemmings, the most abundant species at our site. The combined daily predation rate of avian predators exceeded the maximum daily potential growth rates of both lemming species except at the highest recorded densities for brown lemmings. We thus show, for the first time, that predation pressure exerted without delay by avian predators can limit populations of coexisting lemming species during the snow-free period, and thus, that predation could play a role in the cyclic dynamic of these species in the tundra.</p

Apparent Clustering of Intermediate-redshift Galaxies as a Probe of Dark Energy

We show the apparent redshift-space clustering of galaxies in redshift range of 0.2--0.4 provides surprisingly useful constraints on dark energy component in the universe, because of the right balance between the density of objects and the survey depth. We apply Fisher matrix analysis to the the Luminous Red Galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS), as a concrete example. Possible degeneracies in the evolution of the equation of state (EOS) and the other cosmological parameters are clarified.Comment: 5 pages, 3 figures, Phys.Rev.Lett., replaced with the accepted versio

Use of groundwater lifetime expectancy for the performance assessment of a deep geologic radioactive waste repository:2. Application to a Canadian Shield environment

Cornaton et al. [2007] introduced the concept of lifetime expectancy as a performance measure of the safety of subsurface repositories, based upon the travel time for contaminants released at a certain point in the subsurface to reach the biosphere or compliance area. The methodologies are applied to a hypothetical but realistic Canadian Shield crystalline rock environment, which is considered to be one of the most geologically stable areas on Earth. In an approximately 10\times10\times1.5 km3 hypothetical study area, up to 1000 major and intermediate fracture zones are generated from surface lineament analyses and subsurface surveys. In the study area, mean and probability density of lifetime expectancy are analyzed with realistic geologic and hydrologic shield settings in order to demonstrate the applicability of the theory and the numerical model for optimally locating a deep subsurface repository for the safe storage of spent nuclear fuel. The results demonstrate that, in general, groundwater lifetime expectancy increases with depth and it is greatest inside major matrix blocks. Various sources and aspects of uncertainty are considered, specifically geometric and hydraulic parameters of permeable fracture zones. Sensitivity analyses indicate that the existence and location of permeable fracture zones and the relationship between fracture zone permeability and depth from ground surface are the most significant factors for lifetime expectancy distribution in such a crystalline rock environment. As a consequence, it is successfully demonstrated that the concept of lifetime expectancy can be applied to siting and performance assessment studies for deep geologic repositories in crystalline fractured rock settings.Comment: 14 pages, 14 figures; Water Resources Research, Vol. 44, 200

SILAC-based phosphoproteomics reveals an inhibitory role of KSR1 in p53 transcriptional activity via modulation of DBC1

BACKGROUND We have previously identified kinase suppressor of ras-1 (KSR1) as a potential regulatory gene in breast cancer. KSR1, originally described as a novel protein kinase, has a role in activation of mitogen-activated protein kinases. Emerging evidence has shown that KSR1 may have dual functions as an active kinase as well as a scaffold facilitating multiprotein complex assembly. Although efforts have been made to study the role of KSR1 in certain tumour types, its involvement in breast cancer remains unknown. METHODS A quantitative mass spectrometry analysis using stable isotope labelling of amino acids in cell culture (SILAC) was implemented to identify KSR1-regulated phosphoproteins in breast cancer. In vitro luciferase assays, co-immunoprecipitation as well as western blotting experiments were performed to further study the function of KSR1 in breast cancer. RESULTS Of significance, proteomic analysis reveals that KSR1 overexpression decreases deleted in breast cancer-1 (DBC1) phosphorylation. Furthermore, we show that KSR1 decreases the transcriptional activity of p53 by reducing the phosphorylation of DBC1, which leads to a reduced interaction of DBC1 with sirtuin-1 (SIRT1); this in turn enables SIRT1 to deacetylate p53. CONCLUSION Our findings integrate KSR1 into a network involving DBC1 and SIRT1, which results in the regulation of p53 acetylation and its transcriptional activity

Proteomic profile of KSR1-regulated signalling in response to genotoxic agents in breast cancer

Kinase suppressor of Ras 1 (KSR1) has been implicated in tumorigenesis in multiple cancers, including skin, pancreatic and lung carcinomas. However, our recent study revealed a role of KSR1 as a tumour suppressor in breast cancer, the expression of which is potentially correlated with chemotherapy response. Here, we aimed to further elucidate the KSR1-regulated signalling in response to genotoxic agents in breast cancer. Stable isotope labelling by amino acids in cell culture (SILAC) coupled to high-resolution mass spectrometry (MS) was implemented to globally characterise cellular protein levels induced by KSR1 in the presence of doxorubicin or etoposide. The acquired proteomic signature was compared and GO-STRING analysis was subsequently performed to illustrate the activated functional signalling networks. Furthermore, the clinical associations of KSR1 with identified targets and their relevance in chemotherapy response were examined in breast cancer patients. We reveal a comprehensive repertoire of thousands of proteins identified in each dataset and compare the unique proteomic profiles as well as functional connections modulated by KSR1 after doxorubicin (Doxo-KSR1) or etoposide (Etop-KSR1) stimulus. From the up-regulated top hits, several proteins, including STAT1, ISG15 and TAP1 are also found to be positively associated with KSR1 expression in patient samples. Moreover, high KSR1 expression, as well as high abundance of these proteins, is correlated with better survival in breast cancer patients who underwent chemotherapy. In aggregate, our data exemplify a broad functional network conferred by KSR1 with genotoxic agents and highlight its implication in predicting chemotherapy response in breast cancer

Testing the performance of a blind burst statistic

In this work we estimate the performance of a method for the detection of burst events in the data produced by interferometric gravitational wave detectors. We compute the receiver operating characteristics in the specific case of a simulated noise having the spectral density expected for Virgo, using test signals taken from a library of possible waveforms emitted during the collapse of the core of Type II Supernovae.Comment: 8 pages, 6 figures, Talk given at the GWDAW2002 worksho