6,522 research outputs found
Recommended from our members
Cancer cell lines show high heritability for motility but not generation time
Tumour evolution depends on heritable differences between cells in traits affecting cell survival or replication. It is well established that cancer cells are genetically and phenotypically heterogeneous; however, the extent to which this phenotypic variation is heritable is far less well explored. Here, we estimate the broad-sense heritability (H2) of two cell traits related to cancer hallmarks––cell motility and generation time––within populations of four cancer cell lines in vitro and find that motility is strongly heritable. This heritability is stable across multiple cell generations, with heritability values at the high end of those measured for a range of traits in natural populations of animals or plants. These findings confirm a central assumption of cancer evolution, provide a first quantification of the evolvability of key traits in cancer cells and indicate that there is ample raw material for experimental evolution in cancer cell lines. Generation time, a trait directly affecting cell fitness, shows substantially lower values of heritability than cell speed, consistent with its having been under directional selection removing heritable variation
Droplet Evaporation on Heated Hydrophobic and Superhydrophobic Surfaces
The evaporation characteristics of sessilewater droplets on smooth hydrophobic and structured superhydrophobic heated surfaces are experimentally investigated. Droplets placed on the hierarchical superhydrophobic surface subtend a very high contact angle (∼160°) and demonstrate low roll-off angle (∼1°), while the hydrophobic substrate supports corresponding values of 120° and ∼10°. The substrates are heated to different constant temperatures in the range of 40–60 °C, which causes the droplet to evaporate much faster than in the case of natural evaporationwithout heating. The geometric parameters of the droplet, such as contact angle, contact radius, and volume evolution over time, are experimentally tracked. The droplets are observed to evaporate primarily in a constant-contact-angle mode where the contact line slides along the surface. The measurements are compared with predictions from a model based on diffusion of vapor into the ambient that assumes isothermal conditions. This vapor-diffusion-only model captures the qualitative evaporation characteristics on both test substrates, but reasonable quantitative agreement is achieved only for the hydrophobic surface. The superhydrophobic surface demonstrates significant deviation between the measured evaporation rate and that obtained using the vapor-diffusion-only model, with the difference being amplified as the substrate temperature is increased.Asimple model considering thermal diffusion through the droplet is used to highlight the important role of evaporative cooling at the droplet interface in determining the droplet evaporation characteristics on superhydrophobic surfaces
Droplet evaporation on heated hydrophobic and superhydrophobic surfaces
The evaporation characteristics of sessile water droplets on smooth hydrophobic and structured superhydrophobic heated surfaces are experimentally investigated. Droplets placed on the hierarchical superhydrophobic surface subtend a very high contact angle (similar to 160 degrees) and demonstrate low roll-off angle (similar to 1 degrees), while the hydrophobic substrate supports corresponding values of 120 degrees and similar to 10 degrees. The substrates are heated to different constant temperatures in the range of 40-60 degrees C, which causes the droplet to evaporate much faster than in the case of natural evaporation without heating. The geometric parameters of the droplet, such as contact angle, contact radius, and volume evolution over time, are experimentally tracked. The droplets are observed to evaporate primarily in a constant-contact-angle mode where the contact line slides along the surface. The measurements are compared with predictions from a model based on diffusion of vapor into the ambient that assumes isothermal conditions. This vapor-diffusion-only model captures the qualitative evaporation characteristics on both test substrates, but reasonable quantitative agreement is achieved only for the hydrophobic surface. The superhydrophobic surface demonstrates significant deviation between the measured evaporation rate and that obtained using the vapor-diffusion-only model, with the difference being amplified as the substrate temperature is increased. A simple model considering thermal diffusion through the droplet is used to highlight the important role of evaporative cooling at the droplet interface in determining the droplet evaporation characteristics on superhydrophobic surfaces
Natural Gas as Feedstock for Fertilizer
Separation of the hydrogen needed for the ammonia synthesis reaction, from its source is difficult. Hydrogen production method is the main source of distinction between the various ammonia production routes. Most of the improvements in the technology regarding the ammonia synthesis were concerned with the hydrogen production step. Hydrogen can be produced by steam reforming, partial oxidation and water electrolysis. The bulk of the world ammonia production is based on steam reforming. The major hydrogen sources are natural gas, naphtha and coal. In this project different methods available for hydrogen separation from its source are analyzed and the best possible way to produce synthesis gas (which will form ammonia) from natural gas is found out. The number of reforming stages required for a plant capacity of 1500 tons per day of ammonia production is found out. The mass balance and energy balance calculations for the above said plant capacity is presented in this work. Then the conventional carbon dioxide removal process and methanation process are replaced by the advanced, economical pressure swing adsorption process. It was also found that two stages of shift converters required for this plant capacity. The number of reforming stages required is only one and nitrogen is obtained from oxygen pressure swing absorption units. The oxygen separated is also used as a fuel with natural gas for reforming. The carbon dioxide is separated in another PSA which can be used for the production of urea
Growth of Oriented Au Nanostructures: Role of Oxide at the Interface
We report on the formation of oriented gold nano structures on Si(100)
substrate by annealing procedures in low vacuum (\approx10-2 mbar) and at high
temperature (\approx 975^{\circ} C). Various thicknesses of gold films have
been deposited with SiOx (using high vacuum thermal evaporation) and without
SiOx (using molecular beam epitaxy) at the interface on Si(100). Electron
microscopy measurements were performed to determine the morphology, orientation
of the structures and the nature of oxide layer. Interfacial oxide layer, low
vacuum and high temperature annealing conditions are found to be necessary to
grow oriented gold structures. These gold structures can be transferred by
simple scratching method.Comment: 13 pages, 3 figures, Accepted in J. Appl. Phy
Hazardous oil spill in Mumbai Port and adjacent fishing areas
A catastrophic collision of two
merchant ships occurred in Mumbai
Port on 7th August 2010 which resulted
in spilling of about 800 t bunker oil and
tumbling of 293 cargo containers with
hazardous chemicals in the sea
Yoga Reduces Symptoms of Distress in Tsunami Survivors in the Andaman Islands
A month after the December 2004 tsunami the effect of a 1 week yoga program was evaluated on self rated fear, anxiety, sadness and disturbed sleep in 47 survivors in the Andaman Islands. Polygraph recordings of the heart rate, breath rate and skin resistance were also made. Among the 47 people, 31 were settlers from the mainland (i.e. India, ML group) and 16 were endogenous people (EP group). There was a significant decrease in self rated fear, anxiety, sadness and disturbed sleep in both groups, and in the heart and breath rate in the ML group, and in the breath rate alone in the EP group, following yoga (P < 0.05, t-test). This suggests that yoga practice may be useful in the management of stress following a natural disaster in people with widely differing social, cultural and spiritual beliefs
- …