Plenary Panel Discussion: Challenges and opportunities for the future of control

This panel reflects the scope and diversity of the unprecedented challenges and opportunities for the systems and controls community that has been created by several research themes from the basic sciences to advanced technologies. Connecting physical processes at multiple time and space scales in quantum, statistical, fluid, and solid mechanics, remains not only a central scientific challenge but also one with increasing technological implications. This is particular so in highly organized and nonequilibrium systems as in biology and nanotechnology, where interconnection, feedback, and dynamics are playing an increasingly central role

Vision-related symptoms as a clinical feature of chronic fatigue syndrome/myalgic encephalomyelitis? Evidence from the DePaul Symptom Questionnaire

Chronic Fatigue Syndrome (CFS) or Myalgic Encephalomyelitis (ME) is a debilitating disorder, affecting at least 250,000 people in the UK. Marked by debilitating fatigue, its aetiology is poorly understood and diagnosis controversial. A number of symptoms overlap with other illnesses with the result that CFS/ME is commonly misdiagnosed. It is important therefore that significant clinical features are investigated. People diagnosed with CFS/ME consistently report that they experience vision-related symptoms associated with their illness1-3 with some of these reports being verified experimentally. Although vision-related symptoms may represent a significant clinical feature of CFS/ME that could be useful in its diagnosis, they have yet to be included in clinical guidelines

Effect of cortical-medullary gradient for ammonia on urinary excretion of ammonia

Effect of cortical-medullary gradient for ammonia on urinary excretion of ammonia. Previous studies suggested that a portion of ammonia secreted into the proximal tubule may diffuse directly from Henle's loop into the medullary collecting duct. Since water is absorbed along the course of the descending portion of the loop, it was proposed that the concentration of ammonia increased in loop fluid, and that rapid diffusibility of the free base would facilitate the delivery of ammonia into medullary interstitium where a high level could be maintained by the countercurrent exchange process. In this schema it was proposed that there was an ammonia concentration gradient between medullary structures and cortex, and recovery of ammonia by the medullary collecting duct due to the low pH in tubule fluid at that site. The present study was designed to evaluate this hypothesis by estimating ammonia concentrations in medullary and cortical tissue, and by correlating medullary levels with secretion rate into the inner medullary collecting duct. In control animals the concentration of total ammonia (NH4+ + NH3+) in inner medullary vasa recta was 9.2 ± 1.5 µmoles/ml, a level 100-fold higher than the cortical level of 0.10 ± 0.01. During acute acidosis the medullary level rose to 22.5 ± 2.7 µmoles/ml, but in acute acidosis during mannitol infusion the level fell to 8.0 ± 1.2. The rate of ammonia secretion into inner medullary collecting duct fluid correlated directly with medullary vasa recta ammonia concentration. These data provide evidence for a steep ammonia concentration gradient between the medulla and cortex, and suggest that the diffusion gradient across collecting duct epithelium governs the rate of the addition of ammonia to collecting duct fluid.Effet du gradient cortico-médulaire d'ammoniaque sur l'excrétion urinaire d'ammoniaque. Des études antérieures ont suggéré qu'une partie de l'ammoniaque sécrété dans le tubule proximal pourrait diffuser directement de l'anse de Henlé jusqu'au canal collecteur médullaire. Puisque de l'eau est réabsorbée le long de la partie descendante de l'anse, on a proposé que la concentration d'ammoniaque augmenterait dans le liquide de l'anse, et que la diffusibilité rapide de la base libre pourrait faciliter l'apport d'ammoniaque dans l'interstitium médullaire où son niveau élevé pourrait être maintenu par le processus d'échange à contre-courant. Dans ce schéma, il a été proposé qu'il y avait un gradient de concentration d'ammoniaque entre les structures médullaires et le cortex et une récupération de l'ammoniaque par le canal collecteur médullaire en raison du faible pH du liquide tubulaire à ce niveau. Cette étude a été conçue pour évaluer cette hypothèse en estimant les concentrations d'ammoniaque dans le tissu médullaire et cortical, et en corrélant les niveaux médullaires avec la vitesse de sécrétion dans le canal collecteur médullaire interne. Chez les animaux contrôles, la concentration d'ammoniaque total (NH4+ + NH3+) dans les vasa recta médullaires internes était de 9,2 ± 1,5 µmoles/ml, une valeur 1 000 fois plus élevée que le niveau cortical de 0,10 ± 0.01. Pendant une acidose aiguë, le niveau médullaire s'élevait à 22,5 ± 2,7 μmoles/ml, mais en acidose aiguë au cours d'une perfusion de mannitol, le niveau chutait à 8,0 ± 1,2. La vitesse de sécrétion d'ammoniaque dans le liquide du canal collecteur médullaire interne était directement corrélée avec la concentration d'ammoniaque dans les vasa recta médullaires. Ces données apportent la preuve d'un fort gradient de concentration d'ammoniaque entre la médullaire et le cortex, et suggèrent que le gradient de diffusion à travers l'épithélium du canal collecteur gouverne la vitesse d'addition de l'ammoniaque au liquide du canal collecteur

Addressing Health Care Needs For Frail Seniors In Canada: The Role of InterRAI Instruments

Fiscal pressure on the Canadian health care system results from rising numbers of frail seniors with multiple concurrent medical co-morbidities and geriatric syndromes. Improving outcomes in such seniors is contingent on a comprehensive geriatric assessment (CGA) to identify strengths and deficits and to facilitate the development of a comprehensive care plan. InterRAI instruments are standardized, reliable, and validated suites of tools to conduct CGAs; they offer several benefits, including helping clinicians identify important health issues among patients, develop appropriate care plans, and monitor patient progess. These instruments also provide several benefits beyond the bedside, including quality indicators to assess care quality, and case-mix classification algorithms to facilitate funding of health services. Finally, interRAI instruments, which are implemented in several health care settings across Canada and abroad, provide a standardized and common language that is compatible with electronic medical records and will facilitate greater integration of the health care system

Ariel - Volume 7 Number 2

Editors Mark Dembert Frank Chervanek John Lammie Jim Burke Curt Cumming

Comparison of Growth Morphology in Ge (001) Homoepitaxy Using Pulsed Laser Deposition and MBE

Differences in the homoepitaxy of Ge(001) are explored using a dual MBE/PLD deposition system. With identical substrate preparation, temperature calibration, background pressure and analysis, the system provides a unique comparison of the processes arising only from kinetic differences in the flux and at the surface. All films show mounded growth. At substrate temperatures below 200ºC, PLD films are smoother than MBE films, whereas they are similar at higher temperatures.Engineering and Applied Science

Comparison of Morphology Evolution of Ge(001) Homoepitaxial Films Grown by Pulsed Laser Deposition and Molecular Beam Epitaxy

Using a dual Molecular Beam Epitaxy (MBE)-Pulsed Laser Deposition (PLD) Ultra-High Vacuum chamber, we have conducted the first experiments under identical thermal, background, and surface preparation conditions to compare Ge(001) homoepitaxial growth morphology in PLD and MBE. We find that in PLD with low kinetic energy and in MBE the film morphology evolves in a similar fashion: initially irregularly shaped mounds form, followed by pyramidal mounds with edges of the square-base along directions; the film roughness and mound separation increase with film thickness. In PLD with high kinetic energy, well-defined pyramidal mounds are not observed and the morphology rather resembles that of an ion-etched Ge(001) surface. The areal feature density is higher for PLD films than for MBE films grown at the same average growth rate and temperature. Furthermore, the dependence upon film thickness of roughness and feature separation differ for PLD and MBE. We attribute these differences to the higher yield of defect generation by energetic species in PLD.Engineering and Applied Science