Motorized translation

A computer-controlled motorized translation stage mounted with a retro-reflector is used to vary the pump laser beam path relative to the probe laser beam path and this controls the relative timing between the pump and probe laser beams. Note that a one-foot difference in path length is about 1 ns time delay difference. The picosecond TR experiments are done essentially the same way as the nanosecond TR experiments except that the time-delay between the pump and probe beams are controlled by varying their relative path lengths by the computer-controlled motorized translation stage. Thus, one can refer to the last part of the description of the nanosecond TR experiments in the preceding section and use the pump and probe picosecond laser beams in place of the nanosecond laser beams to describe the picosecond TR experiments. 

We then superpose the two photons at Alice s (Bob s) side in the modes ai, a3 (a2, a4) at a polarizing beam splitter PBS1 (PBS2). Moving the mirror Ml, mounted on a motorized translation stage, allows us to change the arrival time to make the photons as indistinguishable as possible. A further... 

These companies provide complete positioning solutions, motors, translation stages, and vibration isolation equipment. 

Fig. 3. A schematic representation of the original pump applied gradient generating apparatus. The CPU or computer runs the required program to control the microdispenser control unit, and the motorized translational stage. The video camera and monitor are used to ensure proper tilling, washing, and drying of the microdispenser (17,1. ...

The contact angle measurements with the capillary rise technique can be time-consuming, and hence automation of the measurements is desirable. Figure 14.18 shows a schematic of an automated capillary rise apparatus. In the automated capillary rise measurements, the cathetometer, which is used to measure the capillary rise, is replaced by a computer and a microscope on motorized positioning stages. Three computer-controlled motorized translational stages (Micro-control) are used to move a horizontally mounted microscope fitted with a video scanner (Cohu CCD) in three directions, i.e. X, y and z. The x-, y- and z-axis stages... 

In order to help interpret the RSNOM data, two parallel, larger scratches on the silicon wafer, of widths 5 ixm and 3 tm, were mapped using the Raman microprobe equipped with a motorized translation stage (Prior Scientific, U.K.). The spectra were obtained with a NA 0.8 objective and 1 sec exposure time per spectrum. Lorentzian curves were again fitted to the spectra to determine the frequency, width, and intensity of the first-order Raman band from the crystalline silicon. 

Out of necessity, the applications discussed here do not constitute an exhaustive list of potential uses of the FP theory, even just in the cellular context. We apologize to the authors whose work could not be cited. However, the methods and techniques discussed here have been successfully applied to molecular motors, translation, transcription, protein and enzyme dynamics, and signaling. Beyond the context of cell biology, vast literature on FP applications to neurobio-logical systems and population genetics can be found. We point the interested reader to some relevant literature on these topics [49, 52, 53, 72, 74,180-188]. 

Frame with thumbscrews supports substrate Strain increases with each turn of the screw Quasi-static stretch applied Eccentric disks rotated axially by a motor Translates rotary motion into oscillatory linear motion Dynamic stretch applied... 

All motions are insured by six stepping motors sequentially driven by a programmable translator-indexer device fitted with a power multiplexer. 

In a film, the cooperative effort of the different molecular motors, between consecutive cross-linked points, promotes film swelling and shrinking during oxidation or reduction, respectively, producing a macroscopic change in volume (Fig. 18). In order to translate these electrochemically controlled molecular movements into macroscopic and controlled movements able to produce mechanical work, our laboratory designed, constructed, and in 1992 patented bilayer and multilayer103-114 polymeric... 

FIGURE 28-5 Schematic illustration of the movement of cytoskeletal elements in slow axonal transport. Slow axonal transport represents the movement of cytoplasmic constituents including cytoskeletal elements and soluble enzymes of intermediary metabolism at rates of 0.2-2 mm/day which are at least two orders of magnitude slower than those observed in fast axonal transport. As proposed in the structural hypothesis and supported by experimental evidence, cytoskeletal components are believed to be transported down the axon in their polymeric forms, not as individual subunit polypeptides. Cytoskeletal polypeptides are translated on cytoplasmic polysomes and then are assembled into polymers prior to transport down the axon in the anterograde direction. In contrast to fast axonal transport, no constituents of slow transport appear to be transported in the retrograde direction. Although the polypeptide composition of slow axonal transport has been extensively characterized, the motor molecule(s) responsible for the movement of these cytoplasmic constituents has not yet been identified. 

The macroscopic rates measured by radiolabel experiments should not be taken to reflect maximum rates of the motors involved. As with mitochondrial transport, the net rate of slow component proteins reflects both the rate of actual movement and the fraction of a time interval that a structure is moving. The elongate shape of cytoskeletal structures and their potential for many interactions means that net displacements are discontinuous. If a structure is moving at a speed of 2 j,m/s, but on average only moves at that rate for one second out of every 100 seconds, then the average rate for the structure will translate to a net rate of only 0.02 pm/s [31]. 

If the torsional strain generated by DNA translocation is utilized for mobilizing nucleosomes [195] then the direction of translocation will play an important role in determining the direction in which DNA is passed over the nucleosome surface and the orientation in which torsion is altered. Provided that rotation of the remodeling complex is restricted, incremental translocation of the motor towards the nucleosome will apply positive superhelical torsion to the particle whereas translocation away the nucleosome will apply negative superhelical torsion [119] (Fig. 3). The problem then is how to translate the motion of the translocase into translational... 

An option on the MARDTB is to have motorized x, y translations built into the goniometer /-translation along ip is always available. When x, y motors are present an lUCr, Huber goniometer is not used, but the crystal is mounted directly onto the ip axis with a magnetic cap.)... 

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