Itk negatively regulates induction of T cell proliferation by CD28 costimulation

Effects of epidermal growth factor (EGF) and possible mechanisms of EGF-mediated signal transduction were investigated in isolated cells of the digestive gland of the mussel (Mytilus galloprovincialis Lam. ). EGF induced a cytosolic Ca2+ transient and subsequently stimulated DNA synthesis; both effects were dose-dependent in the nanomolar range and inhibited by pretreatment with an inhibitor of tyrosine kinase activity, suggesting specific EGFR-like receptors. The EGF-induced cytosolic Ca2+ transient was mainly due to a Ca2+ influx through the plasma membrane, possibly involving voltage-insensitive Ca2+ channels. Such a Ca2+ response was abolished by pretreatment with indomethacin and NDGA, inhibitors of arachidonic acid metabolism; similarly, the EGF-stimulated increase in DNA synthesis was significantly reduced. Indomethacin, a cyclooxygenase inhibitor, had the greatest effect on both EGF-induced responses. Results suggest the presence of EGF-responsive cells in the mussel digestive gland. A possible role for arachidonic acid and its metabolites in mediating the effects of EGF is also indicated.     

Integrating machine learning in ad hoc routing: A wireless adaptive routing protocol

The nodes in a wireless ad hoc network act as routers in a self‐configuring network without infrastructure. An application running on the nodes in the ad hoc network may require that intermediate nodes act as routers, receiving and forwarding data packets to other nodes to overcome the limitations of noise, router congestion and limited transmission power. In existing routing protocols, the ‘self‐configuring’ aspects of network construction have generally been limited to the construction of routes that minimize the number of intermediate nodes on a route while ignoring the effects that the resulting traffic has on the overall communication capacity of the network. This paper presents a context‐aware routing metric that factors the effects of environmental noise and router congestion into a single time‐based metric, and further presents a new cross‐layer routing protocol, called Warp‐5 (Wireless Adaptive Routing Protocol, Version 5), that uses the new metric to make better routing decisions in heterogeneous network systems. Simulation results for Warp‐5 are presented and compared to the existing, well‐known AODV (Ad hoc On‐Demand Distance Vector) routing protocol and the reinforcement‐learning based routing protocol, Q‐routing. The results show Warp‐5 to be superior to shortest path routing protocols and Q‐routing for preventing router congestion and packet loss due to noise. Copyright © 2011 John Wiley & Sons, Ltd.     

Infant visual attentiveness in relation to birth condition.

28 preterm infants tested at 40 wks conceptional age showed significantly longer periods of attention to 2-dimensional stimuli than did 28 full-term infants of the same conceptional age (Exp I). To determine whether attentiveness of the full-term infants was diminished by transient birth effects, visual attentiveness was measured in a group of 15 full-term infants in the 1st 2 days of life and 2 wks later (Exp II). There was no significant increase in attention over this period. Furthermore, data from 62 additional preterm infants showed that fixation times were not significantly related to length of postnatal experience (Exp III). The only attention measure relating to birth condition was a measure of initial responsiveness. Healthier infants showed slightly longer first fixations on the first exposure of the stimulus. Initial responsiveness to visual stimuli may represent infant attentiveness more accurately than sustained attention to unchanging 2-dimensional stimuli. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Minimum fluid flowrate,pressure drop and stability of a conical spouted bed

A model for calculating the minimum spouting flowrate and pressure drop in a conical spouted bed has been developed and described in our previous paper (Had?ismajlovi et al., 1986). In the present work, this model was examined at a wider range of experimental conditions and it was found that measured and predicted values of the minimum spouting flowrate and pressure drop differed by about 10.3% and 20.0%, respectively. It is shown that the spouted bed in a conical column is stable when the inlet tube diameter is less than 25 particle diameters.     

Fluid flow pattern and solids circulation rate in a liquid phase spout-fluid bed with draft tube

The fluid flow pattern and solids circulation rate in a liquid phase spout-fluid bed with a draft tube were studied in a semi-circular column 196 mm in diameter equipped with a semi-circular draft tube 34.5 mm in diameter using water and spherical glass particles 1.20, 1.94 and 2.98 mm in diameter. Both the solids circulation rate and fluid distribution between the draft tube and the annulus are influenced by the location of the draft tube, the relative magnitude of the inlet spouting and annulus flowrates, and the total fluid flowrate entering the bed. A one-dimensional steady state model of vertical non-accelerating liquid-solids flow predicts the solids mass flux in the draft tube with a mean deviation of 12.3% when experimental values of the axial pressure gradients in the draft tube and annulus are specified. A simple correlation for the fountain height is also presented.     

Democratic approximation of lexicographic preference models

Lexicographic preference models (LPMs) are an intuitive representation that corresponds to many real-world preferences exhibited by human decision makers. Previous algorithms for learning LPMs produce a “best guess” LPM that is consistent with the observations. Our approach is more democratic: we do not commit to a single LPM. Instead, we approximate the target using the votes of a collection of consistent LPMs. We present two variations of this method—variable voting and model voting—and empirically show that these democratic algorithms outperform the existing methods. Versions of these democratic algorithms are presented in both the case where the preferred values of attributes are known and the case where they are unknown. We also introduce an intuitive yet powerful form of background knowledge to prune some of the possible LPMs. We demonstrate how this background knowledge can be incorporated into variable and model voting and show that doing so improves performance significantly, especially when the number of observations is small.     

Exclusive and persistent use of the entry coreceptor CXCR4 by human immunodeficiency virus type 1 from a subject homozygous for CCR5 delta32

Individuals who are homozygous for the 32-bp deletion in the gene coding for the chemokine receptor and major human immunodeficiency virus type 1 (HIV-1) coreceptor CCR5 (CCR5 -/-) lack functional cell surface CCR5 molecules and are relatively resistant to HIV-1 infection. HIV-1 infection in CCR5 -/- individuals, although rare, has been increasingly documented. We now report that the viral quasispecies from one such individual throughout disease is homogenous, T cell line tropic, and phenotypically syncytium inducing (SI); exclusively uses CXCR4; and replicates well in CCR5 -/- primary T cells. The recently discovered coreceptors BOB and Bonzo are not used. Although early and persistent SI variants have been described in longitudinal studies, this is the first demonstration of exclusive and persistent CXCR4 usage. With the caveat that the earliest viruses available from this subject were from approximately 4 years following primary infection, these data suggest that HIV-1 infection can be mediated and persistently maintained by viruses which exclusively utilize CXCR4. The lack of evolution toward the available minor coreceptors in this subject underscores the dominant biological roles of the major coreceptors CCR5 and CXCR4. This and two similar subjects (R. Biti, R. Ffrench, J. Young, B. Bennetts, G. Stewart, and T. Liang, Nat. Med. 3:252-253, 1997; I. Theodoreu, L. Meyer, M. Magierowska, C. Katlama, and C. Rouzioux, Lancet 349:1219-1220, 1997) showed relatively rapid CD4+ T-cell declines despite average or low initial viral RNA load. Since viruses which use CXCR4 exclusively cannot infect macrophages, these data have implications for the relative infection of the T-cell compartment versus the macrophage compartment in vivo and for the development of CCR5-based therapeutics.     

Use of coreceptors other than CCR5 by non-syncytium-inducing adult and pediatric isolates of human immunodeficiency virus type 1 is rare in vitro

We have tested a panel of pediatric and adult human immunodeficiency virus type 1 (HIV-1) primary isolates for the ability to employ the following proteins as coreceptors during viral entry: CCR1, CCR2b, CCR3, CCR4, CCR5, CCR8, CXCR4, Bonzo, BOB, GPR1, V28, US28, and APJ. Most non-syncytium-inducing isolates could utilize only CCR5. All syncytium-inducing viruses used CXCR4, some also employed V28, and one (DH123) used CCR8 and APJ as well. A longitudinal series of HIV-1 subtype B isolates from an infected infant and its mother utilized Bonzo efficiently, as well as CCR5. The maternal isolates, which were syncytium inducing, also used CXCR4, CCR8, V28, and APJ.     

Study of the hydrodynamics within a draft tube spouted bed system

Two dimensional Darcy and Ergun models are used to describe the hydrodynamics within the annulus of a spouted bed equipped with a draft tube. Experimental pressure and stream function data for water spouting are shown to be in good agreement with theoretical predictions. Verification of a general spout-annulus interfacial boundary condition is also established and it is shown that the entry region below the draft tube functions as a classical spouted bed. In addition, an experimental procedure for determining the location of the spout-annulus interface is presented. Fluid residence time distributions are calculated for a few cases of practical interest.