1,220 research outputs found
Sink-Independent Model in Wireless Sensor Networks
Wireless sensor networks generally support users that send queries and receive data via the sinks. The user and the sinks are mostly connected to each other by infrastructure networks. The users, however, should receive the data from the sinks through multi-hop communications between disseminating sensor nodes if such users move into the sensor networks without infrastructure networks. To support mobile users, previous work has studied various user mobility models. Nevertheless, such approaches are not compatible with the existing routing algorithms, and it is difficult for the mobile users to gather data efficiently due to their mobility. To improve the shortcomings, we propose a view of mobility for wireless sensor networks and propose a model to support a user mobility that is independent of sinks
Cysteinyl leukotrienes as novel host factors facilitating Cryptococcus neoformans penetration into the brain
Cryptococcus neoformas infection of the central nervous system (CNS) continues to be an important cause of mortality and morbidity, and a major contributing factor is our incomplete knowledge of the pathogenesis of this disease. Here, we provide the first direct evidence that C. neoformans exploits host cysteinyl leukotrienes (LTs), formed via LT biosynthetic pathways involving cytosolic phospholipase A2α (cPLA2α) and 5â lipoxygenase (5â LO) and acting via cysteinyl leukotriene type 1 receptor (CysLT1), for penetration of the bloodâ brain barrier. Gene deletion of cPLA2α and 5â LO and pharmacological inhibition of cPLA2α, 5â LO and CysLT1 were effective in preventing C. neoformans penetration of the bloodâ brain barrier in vitro and in vivo. A CysLT1 antagonist enhanced the efficacy of an antiâ fungal agent in therapy of C. neoformans CNS infection in mice. These findings demonstrate that host cysteinyl LTs, dependent on the actions of cPLA2α and 5â LO, promote C. neoformans penetration of the bloodâ brain barrier and represent novel targets for elucidating the pathogenesis and therapeutic development of C. neoformans CNS infection.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136343/1/cmi12661_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136343/2/cmi12661.pd
Mapping of noninvasion Tn phoA mutations on the Escherichia coli O18:K1:H7 chromosome
The most virulent newborn meningitis-associated Escherichia coli are of the serotype O18: K1: H7. We previously isolated a large number of E. coli O18:K1:H7 mutants resulting from transposon Tn phoA mutagenesis that fail to invade brain microvascular endothelial cells. We have now determined the locations of 45 independent insertions. Twelve were localized to the 98 min region, containing a 120 kb segment that is characteristic of E. coli O18:K1:H7. Another, the previously described insertion ibe -10::Tn phoA , was localized to the 87 min region, containing a 20 kb segment found in this E. coli . These noninvasion mutations may define new O18:K1:H7 pathogenicity islands carrying genes for penetration of the blood-brain barrier of newborn mammals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75686/1/j.1574-6968.1996.tb08526.x.pd
Physical properties of transparent perovskite oxides (Ba,La)SnO3 with high electrical mobility at room temperature
Transparent electronic materials are increasingly in demand for a variety of
optoelectronic applications. BaSnO3 is a semiconducting oxide with a large band
gap of more than 3.1 eV. Recently, we discovered that La doped BaSnO3 exhibits
unusually high electrical mobility of 320 cm^2(Vs)^-1 at room temperature and
superior thermal stability at high temperatures [H. J. Kim et al. Appl. Phys.
Express. 5, 061102 (2012)]. Following that work, we report various physical
properties of (Ba,La)SnO3 single crystals and films including
temperature-dependent transport and phonon properties, optical properties and
first-principles calculations. We find that almost doping-independent mobility
of 200-300 cm^2(Vs)^-1 is realized in the single crystals in a broad doping
range from 1.0x10^19 to 4.0x10^20 cm^-3. Moreover, the conductivity of ~10^4
ohm^-1cm^-1 reached at the latter carrier density is comparable to the highest
value. We attribute the high mobility to several physical properties of
(Ba,La)SnO3: a small effective mass coming from the ideal Sn-O-Sn bonding,
small disorder effects due to the doping away from the SnO2 conduction channel,
and reduced carrier scattering due to the high dielectric constant. The
observation of a reduced mobility of ~70 cm^2(Vs)^-1 in the film is mainly
attributed to additional carrier-scatterings which are presumably created by
the lattice mismatch between the substrate SrTiO3 and (Ba,La)SnO3. The main
optical gap of (Ba,La)SnO3 single crystals remained at about 3.33 eV and the
in-gap states only slightly increased, thus maintaining optical transparency in
the visible region. Based on these, we suggest that the doped BaSnO3 system
holds great potential for realizing all perovskite-based, transparent
high-frequency high-power functional devices as well as highly mobile
two-dimensional electron gas via interface control of heterostructured films.Comment: 31 pages, 7 figure
- …