Nuclear activation as a high dynamic range diagnostic of laser-plasma interactions

Proton imaging has become a common diagnostic technique for use in laser-plasma research experiments due to their ability to diagnose electric field effects and to resolve small density differences caused through shock effects. These interactions are highly dependent on the use of radiochromic film (RCF) as a detection system for the particle probe, and produces very high-resolution images. However, saturation effects, and in many cases, damage to the film limits the usefulness of this technique for high-flux particle probing. This paper outlines the use of a new technique using contact radiography of (p,n)-generated isotopes in activation samples to produce high dynamic range 2D images with high spatial resolution and extremely high dynamic range, whilst maintaining both energy resolution and absolute flux measurements. (C)007 Elsevier B.V. All rights reserved.

Structure activity studies of mast cell activation and hypotension induced by neuropeptide Y (NPY), centrally truncated and C-terminal NPY analogues

1 Neuropeptide-induced histamine release is thought to occur via receptor-independent mechanisms, with net charge and lipophilicity being important factors.

Influence of alpha-helicity, amphipathicity and D-amino acid incorporation on the peptide-induced mast cell activation

Mast cell activation by polycationic substances is believed to result from a direct activation of G protein alpha subunits and it was suggested that the adaption of amphipathic, alpha-helical conformations would allow the peptide to reach the cytosolic compartment to interact with G proteins (Mousli et al., 1994, Immunopharmacology 27, 1, for review). We investigated the histamine-releasing activity of model peptides as well as analogues of magainin 2 amide and neuropeptide Y with different amphipathicities and alpha-helix content on rat peritoneal mast cells. Amphipathic helicity is not a prerequisite for mast cell activation. Moreover, non-helical magainin peptides with high histamine-releasing activity were less active in the liberation of carboxyfluoresceine from negatively charged liposomes, indicating that peptide-induced mast cell activation and peptide-induced membrane perturbation do not correlate. In contrast to the negligible influence of the secondary structure, amino acid configuration may exert a striking influence on peptide-induced mast cell activation. Thus histamine-release by substance P was markedly impaired when the L-amino acids in the positively charged N-terminal region were replaced by D-amino acids, with [D-Arg(1)]substance P being the most inactive substance P diastereoisomer.

EFFECT OF IN-VIVO AND IN-VITRO LOVASTATIN TREATMENT ON MAST-CELL ACTIVATION

The hydroxymethylglutaryl coenzmye A (HMG CoA) reductase inhibitor lovastatin is used to treat hyperlipidaemia. This agent prevents the isoprenylation of some proteins involved in signal transduction processes and inhibits IgE-receptor-linked mediator release from RBL-2H3 cells. In this study the effect of in vivo and in vitro administration of lovastatin on histamine release from rat peritoneal mast cells was examined. Lovastatin (4 mg/kg/day for 2 weeks) inhibited histamine release induced by concanavalin A (con A) from rat peritoneal mast cells of Hooded-Lister rats and both homozygous lean and obese Zucker rats. In contrast, release induced by antirat IgE (anti-IgE) was only significantly inhibited in cells derived from Hooded-Lister rats and that induced by compound 48/ 80 was not altered. Lovastatin (20 mu M, 24 h, in vitro) caused a significant inhibition of the subsequent histamine release to con A, anti-IgE and compound 48/80 but not to the calcium ionophore A 23187. It is important to determine whether such inhibitory effects are also observed after the chronic, clinical administration of lovastatin and other HMG CoA reductase inhibitors.

Histamine dilutions modulate basophil activation

Background:In order to demonstrate that high dilutions of histamine are able to inhibit basophil activation in a reproducible fashion, several techniques were used in different research laboratories.

Ran Is a Potential Therapeutic Target for Cancer Cells with Molecular Changes Associated with Activation of the PI3K/Akt/mTORC1 and Ras/MEK/ERK Pathways

Purpose: Cancer cells have been shown to be more susceptible to Ran knockdown than normal cells. We nowinvestigate whether Ran is a potential therapeutic target of cancers with frequently found mutations that lead to higher Ras/MEK/ERK [mitogen-activated protein/extracellular signal-regulated kinase (ERK; MEK)] and phosphoinositide 3-kinase (PI3K)/Akt/mTORC1 activities.

Discrete Conditional Phase-type model (DC_Ph) for patient waiting time with a logistic regression component to predict patient admission to hospital

Discrete Conditional Phase-type (DC-Ph) models are a family of models which represent skewed survival data conditioned on specific inter-related discrete variables. The survival data is modeled using a Coxian phase-type distribution which is associated with the inter-related variables using a range of possible data mining approaches such as Bayesian networks (BNs), the Naïve Bayes Classification method and classification regression trees. This paper utilizes the Discrete Conditional Phase-type model (DC-Ph) to explore the modeling of patient waiting times in an Accident and Emergency Department of a UK hospital. The resulting DC-Ph model takes on the form of the Coxian phase-type distribution conditioned on the outcome of a logistic regression model.

Strength development of mortars containing ground granulated blast-furnace slag: Effect of curing temperature and determination of apparent activation energies

The strength development of mortars containing ground granulated blast-furnace slag (ggbs) and portland cement was investigated. Variables were the level of ggbs in the binder, water-binder ratio and curing temperature. All mortars gain strength more rapidly at higher temperatures and have a lower calculated ultimate strength. The early age strength is much more sensitive to temperature for higher levels of ground granulated blast-furnace slag. The calculated ultimate strength is affected to a similar degree for all ggbs levels and water-binder ratios, with only the curing temperature having a significant effect. Apparent activation energies were determined according to ASTM C1074 and were found to vary approximately linearly with ggbs level from 34 kJ/mol for portland cement mortars to around 60 kJ/mol for mortars containing 70% ggbs. The water-binder ratio appears to have little or no effect oil the apparent activation energy. (c) 2005 Elsevier Ltd. All rights reserved.