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A technique is described to image two phases (alumina and spinel) within a metal-matrix composite which takes advantage of charging effects that occur during examination in an SEM. Microscope and specimen parameters which affect the amount of contrast generated via charging are discussed, and imaging strategies are introduced to optimize the effect. “Model” metal-matrix composite specimens were developed to verify the degree of charging in each phase.

A number of mass spectrometry applications are already available as web-based and windows-based systems to calculate isotope pattern and to display the mass spectrum based on the specific molecular formula besides providing necessary information. These applications were evaluated and compared with our new alternative application called Theoretical Isotope Generator (TIG) in terms of its functionality and features provided to prove this new application is working better and performing well. TIG provides extra features than others, complete with several functionality such as drawing, normalizing and zooming the generated graph that convey with the molecular information in a number of formats by providing the details of the calculation and molecules. Thus, any chemist, students, lecturers and researchers from anywhere could use TIG to gain related information on molecules and their relative intensity., {"references":["","C. G. Herbert, R. A. W. Johnston, Mass Spectrometry Basics, CRC Pree LLC, United States, 2003.","M. Winter, University of Sheffield, England. (2005, May 24). [Online]. Available: http://www.shef.ac.uk/chemistry/chemputer/mlxz.html.","M. Winter, WebElements Ltd. (2006, August 16). WebElements 1993-2006 [Online]. Available: http://www.webelements.com.","Scientific Instrument Services. (2005, May 22). [Online]. Available: http://www.sisweb.com/referenc/tools/massdes.htm.","J. Yan. (2005, May 22). Isotope Pattern Calculator v4.0. [Online]. Available: http://www.geocities.com/junhuayan/pattern.htm.","B. Tattershall, University of New Castle, England. (2005, May 24). [Online]. Available: http//www.staff.ncl.ac.uk/bruce.tattershall/software/pat/readme.html","S. S. Limited. (2006, October 12). Isotopes [Online]. Available: http://www.surfacespectra.com/software/isotopes/download.html.","W. D. Callister, Jr., Materials Science And Engineering An Introduction Sixth Edition, John Wiley & Sons Inc, 2003.","K. J. R. Rosman, and P. D. P. Taylor, Isotopic Compositions Of The Elements 1997, International Union Of Pure And Applied Chemistry, Curtin University of Technology, Australia, 1997.\n[10] J. Group. (2006, January 12). Isotopic Distribution [Online]. Available: http://jjorg.chem.unc.edu/personal/monroe/MwtHelp/IsotopicDistribution.htm\n[11] S. Gagnon, Jefferson Lab. (2005, September 6). Isotope [Online]. Available: http://education.jlab.org/glossary/isotope.html."]}

1. In anaesthetized cats extracellular recordings have been made from antidromically identified sympathetic preganglionic neurones, located in the 2nd and 3rd lumbar segments, with axons projecting into the left lumbar sympathetic chain beyond the L4 ganglion. Sympathetic preganglionic neurones have been characterized with respect to: axonal conduction velocities, firing patterns in relation to ECG and phrenic nerve activity, responses to noxious stimuli applied to the ipsilateral hindlimb and ionophoretically applied 5-HT. 2. Two hundred and ninety-seven sympathetic preganglionic neurones were studied. Their axonal conduction velocities (0.5-13.9 m/s) were in the B and C fibre range. Sixty-eight had on-going activity and the remainder were quiescent. Of the 229 quiescent sympathetic preganglionic neurons, 111 were activated by the ionophoretic application of glutamate. 3. Of the 100 sympathetic preganglionic neurones analysed for an ECG-related pattern of discharge, forty-nine had no, and fifty-one had an ECG-related pattern of discharge. Both sympathetic preganglionic neurones with on-going activity and glutamate activated cells exhibited ECG-related patterns of discharge. 4. Only six of fifty sympathetic preganglionic neurones had a respiratory-related activity pattern. Three had maximal discharge during expiration and three during inspiration. 5. Forty-one sympathetic preganglionic neurones were examined for their response to noxious stimulation of the ipsilateral hindlimb. Ten had their activity decreased (seven glutamate-activated, three with on-going activity), seven had their activity increased (four glutamate-activated and three with on-going activity) and twenty-four were unaffected. These results demonstrate that both sympathetic preganglionic neurones with on-going activity and glutamate-activated neurones can be influenced by noxious input. Ten sympathetic preganglionic neurones had properties consistent with them having a skin vasoconstrictor function and three with muscle vasoconstrictor function. 6. Ionophoretic application of 5-HT in the vicinity of fifty-one sympathetic preganglionic neurones caused increases in the discharge of 53%, decreases in the firing of 12% and did not affect the discharge of 35%. 7. Sympathetic preganglionic neurones which had excitatory responses to 5-HT showed only decreased discharge or no response to noxious stimulation of the ipsilateral hindlimb. Conversely, sympathetic preganglionic neurones which had discharge decreased by 5-HT had primarily excitatory responses to noxious inputs. 8. It is concluded that lumbar sympathetic preganglionic neurones consist of a heterogeneous population with respect to their physiological properties and their responses to ionophoretically applied 5-HT: both may be related to function.

1. In cats anaesthetized with alpha-chloralose and artificially respired, stimulation of intestinal receptors with bradykinin caused greater reflex excitation of mesenteric than of renal efferent multifibre nerve activity and significant pressor responses. 2. Activity of all nerve bundles used in this study was inhibited by stimulation of pressoreceptors. Increases in systemic arterial pressure caused inhibition of activity of renal nerves which was significantly greater than that of mesenteric nerves. 3. Spinal transection caused significant decreases in tonic renal nerve activity without altering the ongoing discharge rate of mesenteric nerves. Stimulation of intestinal receptors in spinal cats still caused significant increases is discharge of mesenteric and renal nerves, indicating that this reflex contains a spinal component. 4. Recordings of activity of individual fibres within mesenteric (21) and renal (23) nerves provided information regarding the basis for the multifibre responses to stimulation of intestinal receptors. The same proportion of fibres from both nerves was excited, but the increase in activity of mesenteric fibres was significantly greater than that of renal fibres. 5. Mesenteric fibres could be classified into two groups, based on their sensitivity to pressoreceptor influences. Fibres that exhibited pressoreceptor-independent discharge had the greatest responses to stimulation of intestinal receptors. 6. Following spinal transection the majority of mesenteric fibres continued to fire, whereas most renal fibres became quiescent. 7. The non-uniform pattern of neuronal excitation to chemical stimulation of intestinal receptors was manifest after spinal transection, demonstrating that exclusively spinal pathways can mediate this differential response pattern. 8. These results support the hypothesis that viscero-sympathetic reflexes may be organized to cause preferential excitation of neural activity directed to the organ from which the reflex originates.

1. Discharge of whole mesenteric and renal nerves was recorded in eighteen chloralose-anaesthetized, artificially respired cats. 2. Inhibition of tonic activity of neurones within the rostral ventrolateral medulla (RVLM blockade) by bilateral application of glycine caused significant reductions in discharge of renal and mesenteric nerves, arterial blood pressure and heart rate. The decrease in discharge of renal nerves was significantly greater than that of mesenteric nerves. 3. During the response to glycine application, the spinal cord was transected at the first cervical segment. The magnitude of renal nerve discharge after transection was not different from that during blockade of the RVLM. On the other hand, mesenteric nerve activity increased following spinal cord transection, returning to control levels. 4. Power spectral analysis revealed that mesenteric and renal nerves discharged with periodicities ranging from 1 to 6 Hz. Application of glycine to the RVLM reduced the slow rhythm in firing of mesenteric and renal nerves similarly. Transection of the spinal cord resulted in further reduction in the rhythmicity in discharge of both nerves. 5. The results indicate that excitatory drive from the RVLM is crucial for the maintenance of on-going discharge of renal, but not of mesenteric nerves. However, such inputs are apparently essential to maintain the slow rhythm in firing of both nerves.

Tonically active neurons in the rostral ventrolateral medulla (RVLM) that project to the autonomic regions of the spinal cord are essential for maintenance of arterial blood pressure at normal levels. Microinjection of glycine into the RVLM in anesthetized cats to inhibit the tonic discharge of these neurons caused variable initial responses in renal and mesenteric nerve discharge and arterial blood pressure. These initial responses were consistently followed by more prolonged decreases in renal and mesenteric nerve discharge and decreases in arterial blood pressure. The tonic influences of neurons in the RVLM were found to be distributed unequally to sympathetic nerves because activity of renal nerves was decreased significantly more than that of mesenteric nerves. The variable nerve and cardiovascular responses during the first 1-3 min after glycine injection were not solely due to loading or unloading of baroreceptors because similar initial responses were seen in vagotomized and sinoaortic denervated cats. Additionally, when muscimol was microinjected into the same sites, only consistent and prolonged decreases in nerve discharge and blood pressure occurred. The inhibitory actions of muscimol on RVLM neurons caused significantly greater decreases in renal than mesenteric nerve activity. Together, these findings demonstrate that the tonic discharge of neurons in the RVLM has unequal influences on renal and mesenteric nerves.

Previous experiments in our laboratory have shown that discharge of splenic, mesenteric, and splanchnic nerves is well maintained after spinal cord transection in chloralose-anesthetized cats (8, 9, 11). The primary purpose of this investigation was to determine if maintained sympathetic discharge could be observed after spinal transection in the absence of chloralose anesthesia. In cats anesthetized with alphaxalone-alphadolone, changes in splanchnic discharge, blood pressure, and heart rate caused by decerebration and removal of the forebrain were observed. This procedure decreased blood pressure, increased heart rate, and had no immediate effect on sympathetic discharge or its rhythm (assessed by power density spectral analysis). One hour after decerebration and termination of anesthesia, splanchnic discharge had increased by approximately 36%. Next, effects of spinal cord transection on discharge of splanchnic, mesenteric, and renal nerves were observed in the decerebrate-unanesthetized cats. Splanchnic discharge decreased by 50%, mesenteric nerve discharge was unchanged, and renal nerve discharge decreased by 97%. Therefore, splanchnic nerve discharge was not as well maintained in decerebrate-unanesthetized cats as it had been in chloralose-anesthetized animals, and the remaining splanchnic discharge appeared to affect mesenteric nerves preferentially. Finally, spectral analysis of the splanchnic discharge demonstrated that before cord transection, most of the signal was in the 0- to 6-Hz frequency range, whereas after transection the proportion of signal in this frequency range was significantly reduced and the proportion in higher frequencies (7-25 Hz) was significantly increased. This loss of low-frequency rhythmicity is consistent with findings in our previous studies in chloralose-anesthetized cats.

The paper outlines some of the fundamental features of current knowledge based systems. A scenario for future systems of this type is then developed. Special consideration is given to the machine interface since it pervades all aspects of an intelligent system. An alternative input/ouput architecture is proposed that helps to overcome some of the problems associated with the hardware implementation of systems that demand massively parallel input/output.

Angiotensin II causes increased arterial pressure which may be mediated, in part, by effects on central sympathetic neurons or by interference with central or peripheral components of the baroreceptor reflex. This investigation was undertaken to determine actions of angiotensin II on sympathetic splanchnic efferent and carotid sinus afferent activity in chloralose-anesthetized cats. Neural responses during increases in arterial pressure caused by intracarotid or intravenous administration of angiotensin II were compared with responses to equivalent increases in arterial pressure induced by intravenously injected dextran or phenylephrine. Intracarotid injections of angiotensin II caused variable splanchnic sympathetic responses consisting of increased, decreased, or unchanged activity. In contrast, intravenous infusions of dextran or phenylephrine consistently inhibited sympathetic activity. Carotid sinus afferent activity was increased similarly by intracarotid angiotensin II and intravenous dextran or phenylephrine. Sympathetic and baroreceptor afferent responses to intravenously injected angiotensin II were not significantly different from responses to dextran or phenylephrine. These data demonstrate that angiotensin II can act centrally to excite sympathetic outflow or to interfere with inhibitory influences of arterial baroreceptors.