Integrating an Image-Guided Robot with Intraoperative MRI

Microsurgical techniques, together with the introduction of intraoperative magnetic resonance imaging (MRI), established the need and the environment for the integration of robotics with surgery. In this article, we summarize our experience with intraoperative MRI on 781 neurosurgical patients. Intraoperative MRI demonstrated unsuspected residual pathology in up to 20% of patients. To take full advantage of the imaging environment, an magnetic resonance (MR)-compatible image-guided robot capable of both microsurgery and stereotaxy was designed and constructed. Unique features of the system include the use of non-ferromagnetic materials, an end effector that actuates standard surgical instrumentation, automated tool exchange, and haptic feedback.     

Role transition: Exploratory survey of new counseling faculty.

Conducted a national survey, using a questionnaire based on the organizational theory work of E. H. Schein (1978), to ascertain how 35 new faculty members in departments offering the doctoral degree in counseling or in counseling psychology viewed their transition from graduate students to faculty members. Results show that, of the 5 adjustment tasks described by Schein, deciphering the reward system was reported as the most difficult. Findings are outlined on how Ss (1) felt they were viewed by peers, (2) trusted chairpersons, and (3) identified what helped them most in their role. (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A test system for calibrating flickermeters

This paper describes a new calibration system for testing flickermeters. The test system is used to generate and measure all the combinations of amplitude changes and frequencies required for calibrating flickermeters. Two computer-controlled waveform generators are used to produce the test conditions. The percent modulations of the test waveforms are measured with two high accuracy sampling voltmeters. Digital logic and software control ensures that the modulated signals are only measured when either maximum or minimum modulation occurs. Test data indicates that the percent modulation of the waveforms generated by the calibration system for square wave and sinusoidal modulations are within 0.002% and 0.005%, respectively, of the nominal values specified in IEC Standard 61000-3-3.     

The lateral mixing of fluidised solids through meshed and unmeshed apertures

Rates at which solids mix laterally through meshed and unmeshed openings in vertical partitions subdividing a fluidised bed are reported. The effects on mixing of the superficial gas velocity, particle size, and total and fractional free aperture areas are assessed, and bed expansion data reported.

The flux rate of material through the apertures was found to be directly proportional to the difference between the superficial and the minimum fluidising velocities, and inversely proportional to a power function of the mean particle diameter. Reducing the free area available for passage of material across the bed decreased the circulation flux rate: increasing the total aperture area had the same effect.

These influences on mixing are explained, and the mixing rates and bed expansion data correlated against relevant experimental variables.     

Clustered DNA damages as dosemeters for ionising radiation exposure and biological responses.

Clustered DNA damages--two or more lesions (oxidised bases. abasic sites, or strand breaks) within a few DNA helical turns on opposing strands--are induced in DNA in solution and in vivo in human cells by ionising radiation. They have been postulated to be difficult to repair, and thus of potentially high biological significance. Since the total of clustered damages produced by ionising radiation is at about 3 to 4 times higher levels than double-strand breaks and are apparently absent in unirradiated cells, levels of clustered damages present immediately alter radiation exposure could serve as sensitive dosemeters of radiation exposure. Since some clusters may not be repairable and may accumulate in cells, they might also be useful as integrating dosemeters of biological effects of radiation damage.     

A contribution to the understanding of a.c. anodizing of aluminium

Commercial aluminium has been anodized in 10% v/v sulphuric acid using alternating current. At 20 V no significant differences in colour and thickness between specimens anodized at the neutral and live terminals were detected. At higher voltages the oxide on the neutral specimens was always more yellow and thinner than that on the live specimens. The colouration was attributed to the reduction of sulphate to sulphide during the cathodic half-cycle, no other sulphur-containing species being detected by XPS. EPMA has shown that the total sulphur distribution across the film was practically uniform and independent of the operating conditions, except in thin films, where it was greatest at the free surface. With additions of ferric sulphate to the solution the reduction to sulphide was inhibited and the differences between live and neutral specimens were avoided. The total amount of sulphur remained unchanged at approximately 5% weight and no iron was incorporated in the film.