Nitric oxide synthase-immunoreactive neurons in human and porcine respiratory tract

The presence of nitric oxide synthase (NO-synthase), the enzyme responsible for the production of nitric oxide (NO) from L-arginine, is shown immunocytochemically in the intrinsic neurons of the human and porcine respiratory tract. NO-synthase immunoreactivity is demonstrated in a subpopulation of neurons of the microganglia present in the wall of the extra- and intrapulmonary bronchi as well as in the hilar region of the lung in relation to blood vessels. The immunostaining was also found in some nerve fibers of the respiratory nervous system. Human and porcine lung gave similar results. The possible involvement of NO in the nonadrenergic noncholinergic (NANC) nervous regulation of the lung is discussed.     

The entry of antiviral and antiretroviral drugs into the central nervous system

The ability of antiviral and antiretroviral drugs to enter the brain is a critical issue in the treatment of many viral brain diseases, including HIV-related neurologic disease. Much of the literature concerning nucleoside analog entry into the nervous system focuses on drug levels in the cerebrospinal fluid (CSF), equating these with drug levels in the brain extracellular fluid (ECF) as though the two compartments intermix freely. We review the anatomic and physiologic aspects of drug entry into CSF and into brain ECF, as well as the exchange processes between these two compartments. In most instances drug concentrations in the CSF and ECF compartments bear little relationship to one another and using CSF concentrations to extrapolate brain ECF concentrations may significantly overestimate the latter. Accepted terminology and methodology for making measurements of blood-brain barrier function are discussed. Studies of brain uptake that express results as brain:plasma ratios, or that have used microdialysis, may overestimate the amount of drug reaching the brain. Using published data, we present an estimate of the time course of Zidovudine (AZT) concentrations in brain ECF and show that brain concentrations of AZT will likely be below that necessary to inhibit HIV-1 replication when AZT is administered systemically. Antiviral nucleosides and oligonucleotides appear to have limited entry into the brain when given systemically, which may hinder therapy of viral brain diseases, while some of the protease inhibitors may enter the brain more readily. Alternative methods for increasing antiviral and antiretroviral drug delivery to brain are discussed.     

Dynamic programming implementation on array processor architectures

Dynamic Programming (DP) applies to many signal and image processing applications including boundary following, the Viterbi algorithm, dynamic time warping, etc. This paper presents an array processor implementation of generic dynamic programming. Our architecture is a SIMD array attached to a host computer. The processing element of the architecture is based on an ASIC design opting for maximum speed-up. By adopting a torus interconnection network, a dual buffer structure, and a multilevel pipeline, the performance of the DP chip is expected to reach the order of several GOPS. The paper discusses both the dedicated hardware design and the data flow control of the DP chip and the total array.This work was supported in part by the NATO, Scientific and Environmental Affairs Division, Collaborative Research Grant SA.5-2-05(CRG.960201)424/96/JARC-501.     

Hydriding and Dehydriding Characteristics of Mechanically Alloyed LaMg_(17) Ni Composite Material

Magnesiumandmagnesiumalloyshavebeenin vestigatedashydrogenstoragematerialsforseveralde cadesbecausefarmorehydrogenbyweightcanbestoredinthemthaninmostoftheothercurrentlyknownhydrogenstoragealloys .Moreover ,thehighnaturalabundanceofMg ,itslightmassandenviron mentalcompatibilitypotentiallymakemagnesiumoneofthemostprospectivecandidatesforfuturehydrogenstoragematerials .Unfortunately ,thepracticalappli cationofMganditsalloyshasbeenlimitedonlytocertainstoragedevicebecauseoftheirpoorhydriding dehydr…     

Formation and Characterization of 1.5-Monolayer Self-Assembled InAs/GaAs Quantum Dots Using Postgrowth Annealing

In this paper, we report that low-density InAs/GaAs quantum dots (QDs) can be formed by postgrowth annealing the samples with 1.5-monolayer (ML) InAs coverage, which is thinner than the critical layer thickness for the Stranski-Krastanov growth. The annealing procedure was performed immediately after the deposition of the InAs layer. The effects of annealing time and annealing temperature on the dot density, dot size, and optical characteristics of the QDs were investigated. The optimum annealing conditions to obtain low-density QDs are longer than 60 s and higher than 500degC . Meanwhile, no luminescence can be observed for the wetting-layer, which may suggest that the postgrowth annealing will make the wetting layer thinner and thus reduce the effects of wetting layer on carrier relaxation and recombination. On the other hand, we observe that a decrease of the PL intensity at the annealing conditions of 60 s and 515degC , which is possibly due to the increasing surface dislocations resulted from the In adatom desorption at higher annealing temperature.     

Rolling and Lifting Probabilities for Sediment Entrainment

This study addresses the rolling and lifting probabilities for sediment entrainment by incorporating the probabilistic features of the turbulent fluctuation and bed grain geometry. The lognormally distributed instantaneous velocity and uniformly distributed initial grain position, along with a relation between lift coefficient and particle Reynolds number, are used to extend the theoretical formulation of the entrainment probabilities in smooth-bed flows. The two threshold conditions identified herein enable us to precisely define the probabilities of entrainment in the rolling and lifting modes. The results obtained in this study coincide well with the published data. The lifting probability increases monotonously with the dimensionless shear stress θ, which is consistent with the earlier results yet displays improved agreement with the experimental data. The maximum value of rolling probability, with a magnitude of 0.25, occurs at θ ≈ 0.15. For θ<0.05 (or θ>0.6), the rolling (or lifting) probability makes up more than 90% of the total entrainment probability and thus can be used as an approximation to the total probability of entrainment. The proposed rolling and lifting probabilities are further linked to the two separate criteria for incipient motion to explore the critical entrainment probabilities. The results reveal that a consistent probability corresponding to the critical state of sediment entrainment cannot be found.     

Hermetic Packaging Using Eutectic SnPb Solder and Cr/Ni/Cu Metallurgy Layer

We have developed an easy, low-cost, and low-temperature optoelectronic hermetic packaging technology utilizing the eutectic SnPb solder and the Cr/Ni/Cu bonding pad. Bonding characteristics of the design were investigated in three different setups: silicon-silicon, silicon-glass, and glass-glass samples. Hermeticity was achieved at 200 degC without flux for all samples during the final bonding process. The bonding pads did not dewet during or after the reflow process. By utilizing the eutectic SnPb solder, the self-alignment process can be achieved. Because the bonding process was conducted through visual alignment, original misalignment was estimated to be more than 100 mum. The surface tension of melting solder during the reflow process allowed the samples to self-align and obtain a misalignment of less than 20 mum after solidification, which was 4% of the entire solder width. The bonding strength of the three setups ranged from 3 to 10 MPa. Among the three setups, glass-glass samples appear to have the strongest bonding strength. This low-temperature and cost-effective soldering process has demonstrated its feasibility and potential utilization in optoelectronic packaging     

On Striping Traffic over Multiple IEEE 802.11(b) Wireless Channels

Due to interference, path loss, multipath fading, background noise, and many other factors, wireless communication normally cannot provide a wireless link with both a high data rate and a long transmission range. To address this problem, striping network traffic in parallel over multiple lower-data-rate but longer-transmission-range wireless channels may be used. In this paper, we propose a new striping method and evaluate its performances over multiple IEEE 802.11(b) channels under various conditions. Our extensive simulation results show that this method is quite effective for such an application. S.Y. Wang is an Associate Professor of the Department of Computer Science and Information Engineering at National Chiao Tung University, Taiwan. He received his Master and Ph.D. degree in computer science from Harvard University in 1997 and 1999, respectively. His research interests include wireless networks, Internet technologies, network simulations, and operating systems. He is the author of the NCTUns 2.0 network simulator and emulator, which is being widely used by network and communication researchers. More information about the tool is available at http://NSL.csie.nctu.edu.tw/nctuns.html. C.H. Hwang received his master degree in computer science from NCTU in 2002 and currently is working for a network company. C.L. Chou currently is a third-year Ph.D. student at the Department of Computer Science and Information Engineering, National Chiao TungUniversity (NCTU), Taiwan. He received his master degree in computer science from NCTU in 2002.     

On inversive maximal period polynomials over finite fields

Over finite field GF(q) withq a power of an odd primep, we characterize inversive maximal period polynomials in terms of polynomials of orderq + 1, and then we study some properties of polynomials of orderq + 1.This paper was written while the author was visiting the Institute of Information Processing, Austrian Academy of Sciences, AustriaThe author would like to thank the Institute of Information Processing, Austrian Academy of Sciences, Austria, for its hospitality and for using its facilities