Alteration of oestradiol metabolism in myc oncogene-transfected mouse mammary epithelial cells

Targeted overexpression of the c-myc oncogene induces neoplastic transformation in immortalized, non-tumorigenic mouse mammary epithelial cells (MMEC). Experiments in the present study were conducted to examine whether cellular transformation induced by c-myc oncogene is associated with altered metabolism of 17beta-oestradiol (E2). The parental, MMEC and the stable c-myc transfectant (MMEC/myc3) cell lines were compared for major oestrogen metabolic pathways, namely E2 and E1 interconversion, and C2- and C16alpha-hydroxylation by both high-pressure liquid chromatography (HPLC) analysis and the 3H release assay using specifically labelled [C2-3H]E2 or [C16alpha-3H]E2. The reductive conversion of E1 to E2 was about 14-fold and 12-fold higher than the oxidative conversion of E2 to E1 in MMEC and MMEC/myc3 cells respectively. However, in MMEC/myc3 cells, both reductive and oxidative reactions were decreased by about 32% and 12% relative to those seen in the parental MMEC cells (P = 0.0028). The extent of C16alpha-hydroxylation was increased by 164.3% (P < 0.001), with a concomitant 48.4% decrease (P < 0.001) in C2-hydroxylation in MMEC/myc3 cells; this resulted in a fourfold increase in the C16alpha/C2 hydroxylation ratio in this cell line. Thus, a persistent c-myc expression, leading to aberrant hyperproliferation in vitro and tumorigenesis in vivo, is associated with an altered oestrogen metabolism. However, it remains unclear whether this represents a result of oncogene expression/activation or is rather a consequence of phenotypic transformation of the cells.     

Damage accumulation under repeated reverse stressing of Sn-Ag solder joints

To better understand the effect of repeated reverse stress in solder joints, a new testing method was developed. Tin-silver solder joints were fabricated, constrained between Cu blocks, and then subjected to repeated shear loading in a tensile tester. Constant strain amplitudes were applied to simulate service conditions. However, large loads were used to accelerate the damage accumulation. Microstructural features of the damage were very similar to those found with studies on thermomechanical fatigue (TMF) of small, single shear lap samples. Concentrated-shear banding or striations were observed to form along Sn dendrites. The load behavior of the solder with each cycle and during hold times at the extreme strain amplitude was consistent with damage accumulating with each successive cycle. Effects of strain amplitude, hold times at the stress extremes, number of cycles, and solder-joint thickness were found to play significant roles on the stress-strain behavior and surface damage.     

The effect of temperature on the flow field in a continuous rotating annular electrophoresis column

The effect of a non-uniform temperature profile on the flow field in a continuous rotating annular electrophoresis column is investigated. The momentum balance equation is solved for packed as well as unpacked columns using a centered-difference finite difference technique with a known temperature profile. The packed column analysis utilizes a parallel annular channel model similar to the capillary channel model used in packed bed columns. Results indicate that the changes in density and viscosity as result of the temperature variation have a significant effect on the flow field. Effects of voltage gradient and column geometry are also discussed.     

Seismic probabilistic risk assessment and its impact on margin studies

In recent years a number of seismic probabilistic risk assessments of nuclear power plants have been conducted. These studies have highlighted the significance of seismic events to the overall plant risk and have identified several dominant contributors to the seismic risk. It has been learnt from the seismic PRAs that the uncertainty in the seismic hazard results contribute to the large uncertainty in the core damage and severe release frequencies. A procedure is needed to assess the seismic safety of a plant which is somewhat removed from the influence of the uncertainties in seismic hazard estimates. In the last two years, seismic margin review methodologies have been developed based on the results and insights from the seismic probabilistic risk assessments. They focus on the question of how much larger an earthquake should be beyond the plant design basis before it compromises the safety of the plant. An indicator of the plant seismic capacity called the High Confidence Low Probability of Failure (HCLPF) capacity, is defined as the level of earthquake for which one could state with high confidence that the plant will have a low probability of severe core damage. The seismic margin review methodologies draw from the seismic PRAs, experience in seismic analyses, testing and actual earthquakes in order to minimize the review effort. The salient steps in the review consists of preliminary screening of components and systems, performance of detailed seismic walkdowns and evaluation of seismic margins for components, systems and plant.     

3D foot shape generation from 2D information

Two methods to generate an individual 3D foot shape from 2D information are proposed. A standard foot shape was first generated and then scaled based on known 2D information. In the first method, the foot outline and the foot height were used, and in the second, the foot outline and the foot profile were used. The models were developed using 40 participants and then validated using a different set of 40 participants. Results show that each individual foot shape can be predicted within a mean absolute error of 1.36 mm for the left foot and 1.37 mm for the right foot using the first method, and within a mean absolute error of 1.02 mm for the left foot and 1.02 mm for the right foot using the second method. The second method shows somewhat improved accuracy even though it requires two images. Both the methods are relatively cheaper than using a scanner to determine the 3D foot shape for custom footwear design.     

Drop formation in non-newtonian liquids under pulsed conditions

Drop formation from single nozzles under pulsed flow conditions in non-Newtonian fluids following the power law model has been studied. An existing model has been modified to explain the experimental data. The flow conditions employed correspond to the mixer—settler type of operation in pulsed sieve-plate extraction columns. The modified model predicts the drop sizes satisfactorily. It has been found that consideration of non-Newtonian behaviour is important at low pulse intensities and its significance decreases with increasing intensity of pulsation. Further, the proposed model for single orifices has been tested to predict the sizes of drops formed from a sieve-plate distributor having four holes, and has been found to predict the sizes fairly well in the absence of coalescence.     

Reliability based design rules for column buckling

A load factor design criterion based on a first-order probability theory is derived for the buckling strength of structural steel columns. The load factors and strength factor are evaluated using available information and testresults. It is also shown how different column theories can be compared on the basis of design resistance obtained from each theory. The paper concludes by describing how probabilistic problems can be simplified by using a first order theory.     

An algorithm for hidden line ruled surface display using microprocessor

A simple algorithm for hidden line Ruled Surface graphics, typically used in Radio Astronomy is discussed using low cost microcomputer system built around Motorola 6800 processor and Matrox 256**2 graphics module of raster size 256 × 256 points. Resolution of the plot can be improved by displaying on a bigger raster like 1024 × 1024 points.