A comparative study of activity and dual sensor: activity and minute ventilation pacing responses to ascending and descending stairs

Previous studies with activity-based rate adaptive pacemakers have shown a somewhat paradoxical response when comparing ascending stairs to descending stairs. The objective of this investigation was to measure dual-sensor rate response provided by activity and minute ventilation (MV) compared with activity alone, and with a control group, during ascending and descending stairs. For dual sensor mode, measured mean peak pacing rate with 72 (92) steps per minute was 111 +/- 13 beats/min (124 +/- 14 beats/min) ascending stairs and 81 +/- 7 beats/min (97 +/- 13 beats/min) for descending. For activity mode alone, mean peak pacing rate was 90 +/- 12 beats/min (108 +/- 19 beats/min) ascending stairs and 97 +/- 12 beats/min (123 +/- 17 beats/min) descending. The mean peak control group heart rate ascending stairs for a step rate of 72 (92) steps/min were 116 +/- 11 beats/min (127 +/- 14 beats/min) ascending stairs and for descending 89 +/- 12 beats/min (95 +/- 11 beats/min). While for dual sensor controlled pacing there was a significant difference for ascending and descending stairs at both step rates, there was no difference between going upstairs and downstairs for activity mode alone. Rates with dual sensor did not significantly differ from respective rates of the control group. The mean correlation coefficient between MV and paced rate was 0.85. Pacing heart rates delivered by the dual sensor mode were appropriate for ascending and descending stairs. In contrast to activity mode alone, the peak heart rates for dual sensor mode are higher during ascending than during descending stairs.     

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GaAs planar doped barrier diodes for millimetre-wave detector applications

Epitaxially grown GaAs planar doped barrier diodes have been designed and fabricated into coplanar structures specifically for millimetre-wave zero-bias detector applications. Results at 35 GHz and 94 GHz show that the tangential sensitivity, voltage sensitivity and dynamic range of these devices can significantly exceed those of any comparable Schottky diode detector. This is the first report of such a result.<>     

Getting blood from collective turnips: Volunteer donation in mass blood drives.

Analyzed correlates of volunteer blood donation in 2 separate mass blood drives, based on data from 1,722 university students, 1,080 donors and 642 nondonors. Previous research on blood donor motivation has suggested that altruistic, humanitarian reasons are the chief motives for donation. Present results indicate virtually no association between donorship and altruism (measured by a modified version of Wrightman's Philosophies of Human Nature Scale). Donors were more responsive to social pressure and incentives and less impeded by a free-rider tendency and the costs of giving than were nondonors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Corium retention for high power reactors by an in-vessel core catcher in combination with External Reactor Vessel Cooling

If there were inadequate cooling during a reactor accident, a significant amount of core material could become molten and relocate to the lower head of the reactor vessel, as happened in the Three Mile Island Unit 2 (TMI-2) accident. If it is possible to ensure that the vessel lower head remains intact so that relocated core materials are retained within the vessel, the enhanced safety associated with these plants can reduce concerns about containment failure and associated risk. For example, the enhanced safety of the Westinghouse Advanced 600 MWe Pressurized Water Reactor (AP600), which relied upon External Reactor Vessel Cooling (ERVC) for in-vessel retention (IVR), resulted in the United States Nuclear Regulatory Commission (US NRC) approving the design without requiring certain conventional features common to existing Light Water Reactors (LWRs). Accordingly, IVR of core melt is a key severe accident management strategy adopted by some operating nuclear power plants and proposed for some advanced light water reactors. However, it is not clear that currently-proposed methods to achieve ERVC will provide sufficient heat removal for higher power reactors. A US–Korean International Nuclear Energy Research Initiative (INERI) project has been initiated in which the Idaho National Engineering and Environmental Laboratory (INEEL), Seoul National University (SNU), Pennsylvania State University (PSU), and the Korea Atomic Energy Research Institute (KAERI) will determine if IVR is feasible for reactors up to 1500 MWe. This paper summarizes results from the first year of this 3-year project.     

Conceptual design of an in-vessel core catcher

An enhanced in-vessel core catcher is being designed and evaluated as part of a joint United States (US)–Korean International Nuclear Energy Research Initiative (INERI) investigating methods to insure retention of materials that may relocate to the lower head of a reactor vessel under severe accident conditions in advanced reactors. This enhanced core catcher design consists of several interlocking sections that are machined to fit together when inserted into the lower head. Each section of the core catcher consists of two material layers with an option to add a third layer (if deemed necessary): a base material, which has the capability to support and contain the mass of core materials that may relocate during a severe accident; an insulator coating material on top of the base material, which resists interactions with high-temperature core materials; and an optional coating on the bottom side of the base material to prevent any potential oxidation of the base material during the lifetime of the reactor. This paper summarizes results from thermal, flow, and structural analyses as well as initial scoping materials interaction tests that were completed to support the conceptual design of the core catcher.     

Resonant tunnelling microwave detector diode for power levelling and limiting applications

Resonant-tunnelling GaAs/AlAs diodes have been fabricated and tested as zero-bias microwave detectors at X-band (9.375 GHz). The transfer function is found to exhibit a sharp dip over a small input power range near 0 dBm, with a square law region below and a linear law region above this dip. An explanation as to how this dip arises and an indication of how a diode with such a transfer function could be used in power levelling and limiting applications are given.<>     

Two‐Photon Fluorescent Imaging of Myelination in the Spinal Cord

Myelination is a fundamental biological process in the vertebrate nervous system. Damage to or malformation of myelin can lead to various neurological diseases; for example, demyelination in the spinal cord is a major cause of paralysis of patients suffering from multiple sclerosis and related diseases. The ability to directly track myelin levels in the spinal cord is needed in order to assess the efficacy of therapeutics in promoting myelin repair. To address this unmet need, 4‐((E)‐4‐((E)‐4‐aminostyryl)‐2,5‐dimethoxystyryl)‐N‐methylaniline, known as Case Imaging Compound (CIC), has been developed as a myelin‐targeted fluorescent imaging agent that selectively binds to myelin. CIC was synthesized via an improved route and evaluated as a fluorescent probe for two‐photon fluorescent imaging of myelin in the spinal cord in both demyelinated and dysmyelinated models. In vitro and ex vivo tissue staining both suggest that CIC selectively binds to in animal models. Further evaluation in animal models indicated that CIC is sensitive to differences in myelin content in healthy versus pathological myelin. CIC could potentially be useful in the development and evaluation of novel therapies for multiple sclerosis and other demyelinating diseases.     

VoIP Applied — Lab Bench to Multimedia Service

Voice is an integral element of many of the emerging conversational IP applications found on the Internet. This paper examines the opportunities to provide these types of application at scale and considers some of the difficulties in translating what may be interesting toys on the laboratory bench into genuinely useful public communication services. It characterises early VoIP network service solutions, charting their evolution towards contemporary services and considers some of the types of application that may be possible in the future.