Facial surface scanner

An optical noncontact 3-D digitizing system developed to acquire, process, display, and replicate the surface of the human head is described. The modification of the digitizer to help plan and evaluate facial plastic surgery is discussed. The quality and accuracy of the images produced are examined, and some medically relevant results are considered     

Manipulation of liquid droplets using amphiphilic, magnetic one-dimensional photonic crystal chaperones

The controlled manipulation of small volumes of liquids is a challenging problem in microfluidics, and it is a key requirement for many high-throughput analyses and microassays. One-dimensional photonic crystals made from porous silicon have been constructed with amphiphilic properties. When prepared in the form of micrometre-sized particles and placed in a two-phase liquid such as dichloromethane/water, these materials will accumulate and spontaneously align at the interface. Here we show that superparamagnetic nanoparticles of Fe(3)O(4) can be incorporated into the porous nanostructure, allowing the materials to chaperone microlitre-scale liquid droplets when an external magnetic field is applied. The optical reflectivity spectrum of the photonic crystal displays a peak that serves to identify the droplet. Two simple microfluidics applications are demonstrated: filling and draining a chaperoned droplet, and combining two different droplets to perform a chemical reaction. The method provides a general means for manipulating and monitoring small volumes of liquids without the use of pumps, valves or a microfluidic container.     

Kinetics of esterification of benzyl alcohol with acetic acid catalysed by cation-exchange resin (Amberlyst-15)

Esterification of benzyl alcohol with acetic acid catalysed by Amberlyst-15 (cation-exchange resin) was carried out in a batch reactor in the liquid phase in the temperature range 328–359 K and at 1 atm. The reaction rate increased with increase in catalyst concentration and reaction temperature. Resin particle size and stirrer speed had virtually no effect on the rate under the experimental conditions. The rate data were correlated with a kinetic model based on homogeneous reaction. The apparent activation energy was found to be 73.3 kJ mol^?1 for the formation of benzyl acetate.     

Validating the Itanium 2 exception control unit: a unit-level approach

Each new microprocessor endeavor strives to achieve the performance gains projected by Moore's law. Such performance arises, in part, from innovative and often from complex microarchitectural features. This trend of increasing functional complexity has already exacerbated the challenge of design validation, making validation the critical path to tapeout. Traditional approaches to functional validation include both focused case writing and the development of random-code generators. In either case, this method is limited to engineering "thought" experiments - the human mind can only process a finite set of states in a seemingly infinite machine state space. In April 2000, the functional model for the Itanium 2 design was nearing tape-out quality. Engineers had written most focused cases to satisfy test plan goals; the random-code generators were mature and pounding away at the RTL model with no restrictions; and the bug rate was steadily decreasing for most units. Despite this encouraging trend, engineers were still concerned with the functional quality of the exception control unit (XPN), one of the most control-logic-intensive units on the chip.     

Expression of cyclins A, D2 and D3 in individual normal mitogen stimulated lymphocytes and in MOLT-4 leukemic cells analyzed by multiparameter flow cytometry

Cyclins are regulatory subunits of the cyclin dependent kinases (CDKs), the enzymes that drive the cell through the respective phases and check-points of the cell cycle. The expression of cyclins in non-tumor cells, regulated by timely induction of their synthesis and proteolysis, is scheduled, occurring at discrete periods of the cell cycle. Using multiparameter flow cytometry we have recently observed that expression of cyclins B1 and E in individual normal lymphocytes mitogenically stimulated by phytohemagglutinin (PHA) and lymphocytic leukemic MOLT-4 cells was similar, restricted to particular phases of the cycle: cyclin B1 was detected only in G2+M- and cyclin E in late G1 and early S-phase cells. In the present study we have measured the expression of cyclins A, D2 and D3 in these cells. The presence of cyclin A was restricted to late S and G2 phases, both in the case of lymphocytes and of MOLT-4 cells. Over 95% of the non-stimulated lymphocytes were both cyclin D2 and D3 negative. Mitogenic stimulation with PHA-induced expression of cyclins D2 and D3 in over 50% cells, which corresponds to the percentage of cells that respond to this mitogen in cultures. Expression of these proteins peaked between 8 and 24 h after addition of PHA, and then decreased at the time of cell entrance to S. During exponential growth (48-72 h after stimulation with PHA) expression of the D-type cyclins was diminished: only between 5-10% of the lymphocytes had levels of cyclin D3 as high as G1 cells between 8-24 h after PHA stimulation. Populations of proliferating lymphocytes and MOLT-4 cells were very heterogeneous in terms of expression of D-type cyclins by individual cells. While expression of cyclin D2 in exponentially growing MOLT-4 cells was similar to that of proliferating lymphocytes, the percent of cells expressing cyclin D3 as well as the degree of expression, was higher in MOLT-4 cells, regardless of the phase of the cycle. These results, with our earlier observations of the untimely expression of cyclins B1 and E in several other tumor lines, suggest that altered expression of cyclins may be a frequent feature of malignancy.     

Suspension of solids by bubble agitation

Using fundamental aspects of the fluid mechanics of a single particle, a relation for the velocity of liquid necessary to suspend solid particles in a shallow depth column is derived. This liquid velocity is developed by the movement of the gas bubbles inside the column with the potential energy dissipated by the bubble during its ascent taken as the gain in the kinetic energy of the liquid. This energy brings about sufficient liquid motion to suspend the particles. The corresponding superficial gas velocity to suspend all the particles present in the column is theoretically estimated and compared to experimental values of superficial gas velocities obtained for various solids concentrations. A set pattern of deviation is observed, and empirical correlations are suggested for predicting the superficial gas velocity to suspend a given amount of solid particles in liquid.