[en] This book attempts to assess the current status and future developments of the medical imaging industry. The first chapter contains brief descriptions, of the basic principles of various imaging modalities (radiologic, CT, nuclear, ultrasound, and thermography), and a chapter describing areas of clinical applications for each modality follows. Chapter 3 provides a profile of the industry, listing the various manufacturers of medical imaging products and their share of the market, based on 1976 to 1978 statistics. Chapter 4 describes briefly the current sources of research support (industry versus government agencies) but does not provide data either in absolute dollars or relative amounts. Chapters 5 to 14 cover a broad spectrum of advanced imaging systems by categories, including x-ray (5 and 6), CT (7 and 8), nuclear (9 and 10), ultrasound (11), thermography (12), NMR (13), and miscellaneous (14), and they may be considered the meat of the book because they provide the basis for predictions of future developments in the medical imaging industry

[en] In this paper we discuss the problems associated with performing excitation spectroscopy on impurities and defects in the one micron region of the optical spectrum. We show that this difficult region can be probed successfully using Fourier transform methods. We report preliminary findings of impurity and defect structures of lattice matched InGaAs quantum wells. (author) 4 refs., 5 figs

[en] The system consists of electron suppressed stops and nonintercepting beam pickups with high output bandwidth of (10 kHz) signal processors to allow accurate sampling of the short duration HI beam pulses. The electronics for the stops are straightforward; there are, however, important technical trade-off in the design of the nonintercepting system design. The amplifier input voltage noise and relatively low coupling impedance of the nonintercepting pickups cause the minimum detectable HI current to decrease with the square root of the HI beam pulse length; as the pulse length is shortened, the system timing constraints also become more critical. Although the BIMPS is capable of providing beam pulse durations as short at 10 μs, the minimum pulse length for operation was chosen to be 100 μs. The electronics have time constants of 200 μs allowing measurement accuracies of better than a percent. Since the most rapid modulation frequency used for filling the Cooler is 20 Hz (corresponding to 1 transverse cooling time constant) the HI pulse does not begin to significantly contribute to the radiation levels or to the total beam losses in the cyclotrons until the modulation ratio of HI to LOW beam exceeds 50. copyright 1995 American Institute of Physics

[en] The design use and implementation of simple but highly efficient instrumentation is described, that allows for the possibility of wavelength-resolving optically detected X-ray absorption spectra (OD-XAS) of even the weakest luminescent systems emitting in the range 380-1020 nm (1.2-3.3 eV). The instrument, based on linearly-variable interference filters, provides significant improvement in light throughput as compared with standard grating monochromators, and is used to demonstrate the power of wavelength-resolved OD-XAS in unravelling luminescence processes that are typically encountered in two common types of systems: (i) single-phase materials that possess a combination of radically different recombination pathways and (ii) materials where the recombination mechanisms are essentially invariant throughout the system, but which are chemically phase-separated on a sub-microscopic scale

[en] The use of the bone marrow culture technique was studied as a means to prepare donor marrow for bone marrow transplantation to avoid lethal graft-versus-host disease (GVHD). Preliminary experiments demonstrated the rapid loss of theta-positive cells in such cultures, so that theta-positive cells were not detected after 6 days. Initial experiments in C3H/HeJ (H-2k, Hbbd) recipients prepared with 900 rad demonstrated improved survival when 3-day cultured C57BL/6 (H-2b, Hbbs) donor cells were used in place of hind limb marrow for transplantation. However, hemoglobin typing of recipient animals revealed only short-term donor engraftment, with competitive repopulation of recipient marrow occurring. Subsequent experiments were done in 1,200-rad prepared recipients, with long-term donor engraftment demonstrated. The majority of 1,200-rad prepared animals receiving cultured allogeneic cells died of GVHD, but animals receiving 28-day cultured cells had an improved 90-day survival and a delay in GVHD development over animals receiving hind limb marrow or marrow from shorter times in culture. In addition, animals receiving anti-theta-treated, 3-day nonadherent cells had an improved survival (44%) over animals receiving anti-theta-treated hind limb marrow (20%). These experiments demonstrate modest benefit for the use of cultured cells in bone marrow transplantation across major H-2 histocompatibility complex differences

[en] Greenhouse gases have to the potential to influence global climate change by interfering with the natural process of heat exchange between the earth's atmosphere and outer space. Reducing atmospheric GHG concentrations have become an international priority as evidenced by the signing of the Kyoto Protocol, which would reduce emissions from industrialized countries (Annex 1) by about 5% below 1990 levels during the commitment period 2008-12. There are a number of technical options that could be implemented in order to achieve the proposed reduction target. As for emissions related to electricity generation, perhaps the most important factor over the near term is the improvement in efficiency of using energy at all the stages of the fuel cycle, including fuel preparation and transportation, fuel-to-electricity conversion at the power plant and at the point of end-use (which has not been considered here). Strategies for reducing methane releases during fuel mining and during gas transmission are very relevant. Switching to less carbon intensive or low carbon fuels, such as gas, nuclear power and renewables, will play a major role in reducing emissions. These changes are technically feasible using present day knowledge and experience, require minimal changes in consumer lifestyle, and represent reasonable capital turnover (gas and nuclear for baseload generation and renewables in niche markets or for peak load applications). This article has presented information on GHG emission factors for different fuels using a Full Energy Chain approach, which attempts to quantify the environmental emissions from all stages of electricity generation, i.e. 'cradle-to-grave'. Fossil-fueled technologies have the highest emission factors, with coal typically twice as high as natural gas. Considering the large variations in fuel- to-electricity conversion technology, it can be said that GHG emission factors can be an order of magnitude higher than current solar PV systems and up to two orders of magnitude higher than nuclear and hydropower. GHG estimates for wind and biomass chains lie between solar and nuclear results. One important conclusion cannot be stressed enough: it is that no technology used in connection with energy supply and use - be it electricity production, transport or other - is associated with zero greenhouse gas emissions. Variations in the emission factor for different options, however, can be quite significant. This fact certainly will have an influence in the decision-making process affecting the choice of power plants that will be included in future national energy systems

[en] In the framework of national R-D project KH-09-04 ''Establishment the fundamental basic for the introduction of nuclear power into Vietnam'', 1996-1998, and Technical cooperation project VIE/0/009 ''Prefeasibility study for the introduction of nuclear power plant into Vietnam'', 1997-1999, planning study of energy and nuclear power has been conducted. Based on 3 scenarios (high, based and low) of the Vietnam socio-economic development up to year 2020, the energy demand (forecasting was carried out using computer model MAED. The electricity demand forecast obtained from the MAED is used as one of the basic inputs to the optimization study of the electricity generating sector using the WASP model. In view of the limited, energy supplies form indigenous resources, it has been assumed that imported coal and nuclear power will be considered as the future energy supply options. From the results of optimal electric system expansion found in the study, it can be concluded that nuclear power should be added to the system from 2016 to 2020 depends on national economic development and availability of domestic natural gas sully (author)

[en] For the undamped Kepler potential the lack of precession has historically been understood in terms of the Runge-Lenz symmetry. For the damped Kepler problem this result may be understood in terms of the generalization of Poisson structure to damped systems suggested recently by Tarasov (2005 J. Phys. A: Math. Gen. 38 2145). In this generalized algebraic structure the orbit-averaged Runge-Lenz vector remains a constant in the linearly damped Kepler problem to leading order in the damping coefficient. Beyond Kepler, we prove that, for any potential proportional to a power of the radius, the orbit shape and precession angle remain constant to leading order in the linear friction coefficient

[en] To see if the acute administration of verapamil improves diastolic filling in hypertension (HTN) and to evaluate the time course of this effect, the authors performed supine 40⁰ equilibrium radionuclide angiography in 7 patients (pts.). Absolute LV volumes were measured using a correction for attenuation in each pt. Time activity curves were analyzed by the cubic smoothing spline technique and peak ejection rate (PER) and peak filling rate (PFR) were determined. By 3-6 min all measurements except HR were similar to PRE. Thus, in pts with HTN, acute administration of verapamil produces rapid transient increase in PFR independent of change in HR or BP

[en] The known metastable defects are usually describable by a configuration coordinate diagram in which two energy minima are separated by a barrier. This diagram does not change with temperature and each configuration is stable over some temperature range. Here we report the observation of a novel metastability: A configuration change occurs spontaneously and abruptly at a critical temperature, giving rise to a discontinuous DLTS (deep level transient spectroscopy) spectrum. We propose that this phenomenon is a manifestation of entropy variations in the configurational space. (author) 12 refs., 4 figs