Micropatterned Surfaces for the Study of Cancer and Endothelial Cell Interactions with Hyaluronic Acid

Hyaluronic acid (HA) is a glycosaminoglycan component of the extracellular matrix. Studies have shown that various cancers exhibit high levels of HA content, and that an increased amount of HA corresponds to poor patient prognosis. HA has been implicated in cellular interactions that are associated with cancer progression, including cell adhesion, motility, and differentiation. Micropatterned functional HA surfaces were developed to study interactions between cancer cells and HA. The adhesion and migration of cancer cells representing different stages of tumorigenesis were examined. A similar surface patterning approach was used to create HA regions next to fibronectin in two- and three-dimensional settings to visualize and study the interactions between cancer and endothelial cells. The ability to observe the dynamic interactions of cancer cells and angiogenesis within a HA-rich microenvironment will improve the fundamental understanding of cancer progression and contribute to the development of advanced therapeutic targets.     

Inhibition of Nitrosomonas europaea by Monoterpenes from Coastal Redwood (Sequoia sempervirens) in Whole-Cell Studies

Inhibition by allelochemicals, including monoterpenes, has been suggested as a factor in the extremely low nitrification rates observed in coastal redwood forests. Similarities between the molecular structure of known nitrification inhibitors and some conifer monoterpenes have been suggested as one reason for the inhibition of autotrophic nitrifiers by conifer monoterpenes. The effect of monolerpenes on nitrification rate and growth of Nitrosomonas europaea was examined in whole-cell pure culture experiments using the five most abundant monoterpenes in coastal redwood needles. These are (in order of decreasing concentration in the needles) limonene, α-pinenc, sabinene, myrcene, and γ-terpinene. Four of the five compounds significantly inhibited growth of N. europaea in batch culture experiments. Short-term kinetic studies of the two most inhibitory monoterpenes, limonene and α-pinene, were performed on whole cells to evaluate the mode of interaction between these chemicals and nitrification rates. Inhibition constants (K _i) of limonene (38 μM) and α-pinene (95 μM) were determined. Lineweaver-Burk plots of nitrification in the presence of monoterpenes appear to fit a noncompetitive inhibition model; however, the mechanisms of inhibition may be more complex.     

A study of the discriminability of shape symbols by the foot

An experiment to test the discriminability of shape symbols using the shod foot was performed with 38 blind people (aged 23-72 years). Ten shape symbols which were 5 mm thick and fitted into a 30.5 cm2 tile were presented to subjects to identify by using only their feet. Each subject had 20 trials in which to discriminate the symbols. In each trial, a symbol was selected randomly and presented to the subject in randomized orientation. The subject was instructed to step on the symbol and to identify it using their own method. Time to discriminate a symbol and the accuracy of identification were recorded. A very high accuracy (93% on average) was obtained, which is comparable to the accuracy of tactile symbol discrimination using the hands. Average time to discriminate a symbol was 16 s with a standard deviation of 12.15 s, which indicated the high variability of the results. Owing to the high accuracy of identification, tactile foot-discriminable symbols have great potential as landmarks for blind people and if applied to a tactile guide path they could provide information for orientation and navigation.     

Macrosegregation in quiescent melting and liquid-phase sintering

Macrosegregation during melting of alloys can arise if the densities of the alloy components differ. In particular, if the higher-melting component is not present in amounts sufficient to develop an interconnected structure, this component can sink (assuming it is more dense than the liquid) to the crucible bottom during melting. This produces a liquid head consisting of (to a first approximation) the pure lower-melting component. The resulting macrosegregation takes considerable time to eliminate since it exists over a macroscopic distance (that over which the particles sink). Similar considerations apply to liquid-phase sintering, also treated in this article. The tendencies for macrosegregation and the subsequent structure evolution in melted/sintered materials can be summarized in a melting map. Such a map has axes of alloy overall composition and alloy liquidus composition. The development and elimination of macrosegregation proceeds in stages. Following initial particle settling, the liquid in the liquid-plus-solid zone near the crucible bottom, which was generated by the settling, attains its equilibrium composition. Finally, elimination of the long-range liquid concentration gradient takes place. If the material has a composition corresponding to a liquid-phase-sintered alloy, the solid in the liquid-plus-solid zone then attains its equilibrium composition. The times for the various stages can be estimated simply. Melting maps can be refined by placing contours of equilibration time on them.     

Summary of Deepwater Sediment/Pore Water Characterization for the Metal-laden Berkeley Pit Lake in Butte, Montana

Abstract.  Unconsolidated sediment at the bottom of the Berkeley pit lake is a mixture of detrital silicate minerals derived from sloughing of the pit walls and secondary minerals precipitated out of the water column. The latter include gypsum and K-rich jarosite. The pore waters have a similar pH to the overlying lake waters (pH 3.1 to 3.4), and have similarly high concentrations of dissolved heavy metals, including Al, Cd, Cu, Mn, Ni, and Zn. Sediment cores show that the top meter of the sediment column is moderately oxidized (jarosite-stable). Petrography, chemical analysis and geochemical modelling all suggest a transformation of poorly crystalline ferric compounds such as schwertmannite and/or ferrihydrite near the sediment surface to jarosite with depth in the core. No evidence of bacterial sulfate reduction was found in this study, despite the presence of 0.3 to 0.4 wt% organic carbon in the pit lake sediment.     

Development of a hydrogen fuelling infrastructure in the Northeast U.S.A.

Development of critical selection criteria was undertaken, identifying locations for possible hydrogen refuelling stations depending on population density, demographics and traffic density. This identified suitable locations for the initial installations of refuelling stations when the first hydrogen fuel cell vehicles became commercially available. This was continued through the three time phases to implement an expanding network of refuelling stations to service demand and ensure consumer convenience.     

Texture, proteolysis and viable lactic acid bacteria in commercial cheddar cheeses treated with high pressure

High pressure processing was investigated for controlling Cheddar cheese ripening. One-month-or 4-month-old Cheddar cheeses were subjected to pressures ranging from 200 to 800 MPa for 5 min at 25 C. The number of viable Lactococcus lactis (starter) and Lactobacillus (nonstarter) cells decreased as pressure increased. Subsequent storage of the control and pressure-treated cheeses at 10 degrees C caused viable cell counts to change in some cases. Free amino acid content was monitored as an indicator of proteolysis. Cheeses treated with pressures > or = 400 MPa evolved free amino acids at significantly lower rates than the control. No acceleration in free amino acid development was observed at lower pressures. Pressure treatment did not accelerate the rate of textural breakdown compared with the non-pressure treated control. On the contrary, pressure treatment at 800 MPa reduced the time-dependent texture changes. Results indicate that high pressure may be useful in arresting Cheddar cheese ripening.     

Morphological factors influencing the initial stages of coarsening in the Al-Al3Ni eutectic composite

The initial stages of microstructural coarsening, in the form of decreased transverse fiber density, in the Al-Al₃Ni eutectic are strongly influenced by the presence of longitudinally misoriented fibers. In transverse sections of directionally solidified alloys, these fibers appear as “bands” of fibers with diameters greater than those of fibers between bands. The initial stages of coarsening are associated with mass transport of nickel from the latter to the former. The initial coarsening rates and transient times were observed to depend strongly on initial band spacing and solidification rate. During this period, the evolving microstructural morphology is similar to that of the initial band morphology. At later stages, the coarsened morphology no longer reflects the original band pattern. A simplified one-dimensional model of transverse coarsening was developed which illustrates the effects that initial band spacing, initial fiber size variation, and solidification rate have on the initial coarsening rate and subsequent microstructural morphology.