Internal Jugular Vein Cross-Sectional Area and Cerebrospinal Fluid Pulsatility in the Aqueduct of Sylvius: A Comparative Study between Healthy Subjects and Multiple Sclerosis Patients

Objectives Constricted cerebral venous outflow has been linked with increased cerebrospinal fluid (CSF) pulsatility in the aqueduct of Sylvius in multiple sclerosis (MS) patients and healthy individuals. This study investigates the relationship between CSF pulsatility and internal jugular vein (IJV) cross-sectional area (CSA) in these two groups, something previously unknown. Methods 65 relapsing-remitting MS patients (50.8% female; mean age = 43.8 years) and 74 healthy controls (HCs) (54.1% female; mean age = 43.9 years) were investigated. CSF flow quantification was performed on cine phase-contrast MRI, while IJV-CSA was calculated using magnetic resonance venography. Statistical analysis involved correlation, and partial least squares correlation analysis (PLSCA). Results PLSCA revealed a significant difference (p<0.001; effect size = 1.072) between MS patients and HCs in the positive relationship between CSF pulsatility and IJV-CSA at C5-T1, something not detected at C2-C4. Controlling for age and cardiovascular risk factors, statistical trends were identified in HCs between: increased net positive CSF flow (NPF) and increased IJV-CSA at C5-C6 (left: r = 0.374, p = 0.016; right: r = 0.364, p = 0.019) and C4 (left: r = 0.361, p = 0.020); and increased net negative CSF flow and increased left IJV-CSA at C5-C6 (r = -0.348, p = 0.026) and C4 (r = -0.324, p = 0.039), whereas in MS patients a trend was only identified between increased NPF and increased left IJV-CSA at C5-C6 (r = 0.351, p = 0.021). Overall, correlations were weaker in MS patients (p = 0.015). Conclusions In healthy adults, increased CSF pulsatility is associated with increased IJV-CSA in the lower cervix (independent of age and cardiovascular risk factors), suggesting a biomechanical link between the two. This relationship is altered in MS patients

New Directions towards the Understanding of Physico-Chemical Processes in Aquatic Systems.

Some applications of Analytical Electron Microscopies (AEM) for the characterization of colloids in natural waters are presented. These techniques go much beyond the basic level of morphological observation and render possible to gain detailed physico-chemical information difficult to obtain by conventional analytical methods. Hence, AEM appear as a challenging necessity for understanding the colloid-mediated transport of toxics in the environment

O2 consumption by the fick method. Methodologic factors.

This study aimed to compare O2 consumption (VO2) determination by the gas-exchange (VO2GE) and Fick (VO2F) methods in cardiac surgical patients. A total of 10 mechanically ventilated postoperative patients were studied prospectively. Thermodilution was performed using three randomly applied techniques: room temperature saline injected at end expiration, room temperature saline randomly injected in the respiratory cycle, and iced saline injected at end expiration. The influence of the number of thermodilution determinations was assessed by comparing results from 2 and 10 injections. The variability of VO2F was greater than that of VO2GE. There was no bias between VO2GE and VO2F values using injectate at room temperature. Accuracy and precision were not improved by increasing the number of cardiac output determinations from 2 to 10. A significant bias was observed using ice-cold injectate, VO2F being 18.0 +/- 15.4 ml/min/m2 lower than VO2GE (p = 0.001). Published results when comparing VO2F and VO2GE are discrepant. However, a significant bias was found in all studies using cold injectate, with lower VO2F values. We conclude that iced injectate should not be used to assess VO2 in critically ill patients

SRAL, A RADAR ALTIMETER DESIGNED TO MEASURE A WIDE RANGE OF SURFACE TYPES

SCOPE In the context of Global Monitoring for Environment and Security (GMES), the objectives of the Sentinel-3 mission driven by ESA encompass the commitment to consistent, long-term collection of remotely sensed data of uniform quality in the areas of sea/land topography and ocean colour. The Sentinel-3 satellite indeed carries a topography mission including mainly RF instruments and an ocean and land colour mission composed of optical instruments. The aim of this paper is to describe the core instrument of the topography mission [1], the SRAL radar altimeter [2], and its latest development steps. OVERVIEW OF SRAL MISSION REQUIREMENTS The SRAL (Sar Radar ALtimeter) instrument is not only specified to retrieve the classical parameters used in the oceanography field such as the Sea Surface Height (SSH), the Significant Wave Height (SWH) and the sea wind speed but it also makes it possible to perform range measurements over the following surfaces: Sea ice Ice sheet interiors (e.g. Antartic plateau) Ice margins In-land waters To achieve these objectives, SRAL will be supported by the other elements of the topography payload : A microwave radiometer which corrects for the tropospheric delay; A real-time navigation system implemented by a GPS equipment; A Laser Retro-Reflector Assembly to provide calibration of range measurements. The SRAL mission requirements and the topography payload will be reminded in the first section of this paper. SRAL MAIN FUNCTIONS SRAL is a nadir-looking radar operating in dual frequency (Ku-band used as main frequency and Cband used for ionospheric corrections over ocean). The nadir swath allows using the simple deramp technique to perform radar pulse compression