1,686 research outputs found

    The molecular basis of lung cancer: molecular abnormalities and therapeutic implications

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    Lung cancer is the number one cause of cancer-related death in the western world. Its incidence is highly correlated with cigarette smoking, and about 10% of long-term smokers will eventually be diagnosed with lung cancer, underscoring the need for strengthened anti-tobacco policies. Among the 10% of patients who develop lung cancer without a smoking history, the environmental or inherited causes of lung cancer are usually unclear. There is no validated screening method for lung cancer even in high-risk populations and the overall five-year survival has not changed significantly in the last 20 years. However, major progress has been made in the understanding of the disease and we are beginning to see this knowledge translated into the clinic. In this review, we will summarize the current state of knowledge regarding the cascade of events associated with lung cancer development. From subclinical DNA damage to overt invasive disease, the mechanisms leading to clinically and molecularly heterogeneous tumors are being unraveled. These lesions allow cells to escape the normal regulation of cell division, apoptosis and invasion. While all subtypes of non-small cell lung cancer have historically been treated the same, stage-for-stage, recent technological advances have allowed a better understanding of the molecular classification of the disease and provide hypotheses for molecular early detection and targeted therapeutic strategies

    Characterization of graphene nano platelets reinforced wellbore cement

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    To improve the mechanical performance of wellbore cement under subsurface environments, graphene nanoplatelets (GNPs) are added in various percentages to Class-H cement slurry. Microstructural characterization of cement slurry cured at 90 degrees C and 95%RH indicates GNP modifies the microstructure of hydrated cement by reinforcing pore spaces. As an apparent result, the axial strength increases up to 27%, elastic stiffness decreases as much as 25% when 0.008% to 0.1%bwoc (by weight of cement) of graphene is added to the cement. Furthermore, the overall behavior of GNP- Portland cement paste is more ductile when compared to neat cement paste. From our observations, graphene enhances the flexibility of cement. The improvements would potentially reduce the risks associated with wellbore leakage primarily in plugging and abandonment but potential in other areas such as fossil fuel production, geothermal energy production, and CO2 storage

    Science requirements and the design of cabled ocean observatories

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    The ocean sciences are beginning a new phase in which scientists will enter the ocean environment and adaptively observe the Earth-Ocean system through remote control of sensors and sensor platforms. This new ocean science paradigm will be implemented using innovative facilities called ocean observatories which provide unprecedented levels of power and communication to access and manipulate real-time sensor networks deployed within many different environments in the ocean basins. Most of the principal design drivers for ocean observatories differ from those for commercial submarine telecommunications systems. First, ocean observatories require data to be input and output at one or more seafloor nodes rather than at a few land terminuses. Second, ocean observatories must distribute a lot of power to the seafloor at variable and fluctuating rates. Third, the seafloor infrastructure for an ocean observatory inherently requires that the wet plant be expandable and reconfigurable. Finally, because the wet communications and power infrastructure is comparatively complex, ocean observatory infrastructure must be designed for low life cycle cost rather than zero maintenance. The origin of these differences may be understood by taking a systems engineering approach to ocean observatory design through examining the requirements derived from science and then going through the process of iterative refinement to yield conceptual and physical designs. This is illustrated using the NEPTUNE regional cabled observatory power and data communications sub-systems

    Quand le comportement découvrit les neurones…

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    Dans les années 1960, Pierre Drach, alors directeur adjoint du CNRS pour les sciences exactes, préconise, dans le cadre du 3e plan, la création d’un institut de psychophysiologie. François Clarac et Jean Massion reviennent sur la genèse d’un institut qui profitait de la décentralisation et de la présence d’un pôle fort en neurologie à Marseille.François Clarac and Jean Massion recount the creation of an institute dedicated to psychophysiology and neurophysiology in the 1960s in Marseille

    The magnitude of the effect of calf muscles fatigue on postural control during bipedal quiet standing with vision depends on the eye-visual target distance

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    The purpose of the present experiment was to investigate whether, with vision, the magnitude of the effect of calf muscles fatigue on postural control during bipedal quiet standing depends on the eye-visual target distance. Twelve young university students were asked to stand upright as immobile as possible in three visual conditions (No vision, Vision 1m and Vision 4m) executed in two conditions of No fatigue and Fatigue of the calf muscles. Centre of foot pressure displacements were recorded using a force platform. Similar increased variances of the centre of foot pressure displacements were observed in the fatigue relative to the No fatigue condition for both the No vision and Vision 4m conditions. Interestingly, in the vision 1m condition, fatigue yielded: (1) a similar increased variance of the centre of foot pressure displacements to those observed in the No vision and Vision 4m conditions along the medio-lateral axis and (2) a weaker destabilising effect relative to the No vision and Vision 4m conditions along the antero-posterior axis. These results evidence that the ability to use visual information for postural control during bipedal quiet standing following calf muscles fatigue is dependent on the eye-visual target distance. More largely, in the context of the multisensory control of balance, the present findings suggest that the efficiency of the sensory reweighting of visual sensory cues as the neuro-muscular constraints acting on the subject change is critically linked with the quality of the information the visual system obtains

    What is the role body sway deviation and body sway velocity play in postural stability in older adults?

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    Summary: This cross sectional study focused on how Postural Stability (PS) indicators: body sway deviation (BSD) and body sway velocity (BSV), change with age and their association with levels of social and physical activity. Observational study: 80 older adults (aged: 60–96) were purposefully recruited from two sources: the University of the Third Age (TAU) (n = 35) and a residential care home (CH) (n = 45). Differences in the indicators of PS, approximated through Centre of Pressure (COP) measurements, were assessed by the Romberg Stance Test (Test A) subsequently repeated on 10 cm foam surface (Test B), using a Kistler® Dynamometric Platform. The RCH Group was older, had higher BMI and was less socially and physically active, showed more body sway in all indicators compared to TAU group. For all participants body sway velocity (BSV) was significantly correlated with age. The strength of correlation of body sway deviation (BSD) with age was also significant but not as strong. The findings indicate in line with previous studies that deterioration in BSV is associated with poor PS more than deterioration in BSD

    Scaling-violation phenomena and fractality in the human posture control systems

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    By analyzing the movements of quiet standing persons by means of wavelet statistics, we observe multiple scaling regions in the underlying body dynamics. The use of the wavelet-variance function opens the possibility to relate scaling violations to different modes of posture control. We show that scaling behavior becomes close to perfect, when correctional movements are dominated by the vestibular system.Comment: 12 pages, 4 figures, to appear in Phys. Rev.

    A Pinned Polymer Model of Posture Control

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    A phenomenological model of human posture control is posited. The dynamics are modelled as an elastically pinned polymer under the influence of noise. The model accurately reproduces the two-point correlation functions of experimental posture data and makes predictions for the response function of the postural control system. The physiological and clinical significance of the model is discussed.Comment: uuencoded post script file, 17 pages with 3 figure
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