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Notes: Gamma-neutron activation experiments have been performed with relativistic electron beams produced by a laser wakefield accelerator. The electron beams were produced by tightly focusing (spot diameter (approximate)6 μm) a high power (up to 10 TW), ultra-short (≥50 fs) laser beam from a high repetition rate (10 Hz) Ti:sapphire (0.8 μm) laser system, onto a high density (〉1019 cm−3) pulsed gasjet of length (approximate)1.5 mm. Nuclear activation measurements in lead and copper targets indicate the production of electrons with energy in excess of 25 MeV. This result was confirmed by electron distribution measurements using a bending magnet spectrometer. Measured γ-ray and neutron yields are also found to be in reasonable agreement with simulations using a Monte Carlo transport code. © 2001 American Institute of Physics.

Notes: We report laser oscillation at ∼610 nm in aggregates of ultrasmall elemental Si nanoparticles. The particles are ultrabright red emitting, dispersed from bulk Si by electrochemistry. The aggregates are excited by radiation at 550–570 nm from a mercury lamp. Intense directed Gaussian beams, with a threshold, manifest the emission. We observe line narrowing, and speckle patterns, indicating spatial coherence. This microlasing constitutes an important step towards the realization of a laser on a chip, hence optoelectronics integration and optical interconnects. © 2002 American Institute of Physics.

Notes: We demonstrate that electrochemically etched, hydrogen capped SinHx clusters with n larger than 20 are obtained within a family of discrete sizes. These sizes are 1.0 (Si29), 1.67 (Si123), 2.15, 2.9, and 3.7 nm in diameter. We characterize the particles via direct electron imaging, excitation and emission optical spectroscopy, and colloidal crystallization. The band gaps and emission bands are measured. The smallest four are ultrabright blue, green, yellow and red luminescent particles. The availability of discrete sizes and distinct emission in the red, green and blue (RGB) range is useful for biomedical tagging, RGB displays, and flash memories. © 2002 American Institute of Physics.

Notes: Abstract: The mechanism of attachment of acetylcholinesterase (AChE) to neuronal membranes in interneuronal synapses is poorly understood. We have isolated, sequenced, and cloned a hydrophobic protein that copurifies with AChE from human caudate nucleus and that we propose forms a part of a complex of membrane proteins attached to this enzyme. It is a short protein of 136 amino acids and has a molecular mass of 18 kDa. The sequence contains stretches of both hydrophobic and hydrophilic amino acids and two cysteine residues. Analysis of the genomic sequence reveals that the coding region is divided among five short exons. Fluorescence in situ hybridization localizes the gene to chromosome 6p21.32-p21.2. Northern blot analysis shows that this gene is widely expressed in the brain with an expression pattern that parallels that of AChE.

Notes: In order to be able to monitor dispersion and setting of cements, admixtures can be added, which usually can consist of large organic molecules. Here, the choice is different since small organic molecules have been used as in ceramic processing. This work concerns the preparation of calcium aluminate cement paste in the presence of acetic acid; the water to cement mass ratio is equal to 0.6 and the acid to cement mass ratio, 〈inlineGraphic alt="inline image" href="urn:x-wiley:00027820:JACE00414:JACE_00414_mu15" location="equation/JACE_00414_mu15.gif"/〉 , ranges between 0 and 0.05. This admixture can have either a retarding or an accelerating effect on cement setting. The retarding effect is because of adsorption of acetate complexes, CaCH3CO2+ positively charged, at the surface of CA particles, negatively charged, which leads to the delay (slowing down) of dissolution; it can reach 52 h (case of 〈inlineGraphic alt="inline image" href="urn:x-wiley:00027820:JACE00414:JACE_00414_mu16" location="equation/JACE_00414_mu16.gif"/〉 ). When 〈inlineGraphic alt="inline image" href="urn:x-wiley:00027820:JACE00414:JACE_00414_mu17" location="equation/JACE_00414_mu17.gif"/〉 , there is a remarkable accelerating effect. The setting starts 2 h after mixing the cement with the liquid and is fairly constant for higher acetic acid contents. This rapid setting in acid conditions is because of the formation of hydrated calcium acetate in very low quantities and possibly gibbsite; the setting mechanism is quite different since there is no formation of conventional calcium and aluminum hydrates. As an example, with the highest amount of HOAc ( 〈inlineGraphic alt="inline image" href="urn:x-wiley:00027820:JACE00414:JACE_00414_mu18" location="equation/JACE_00414_mu18.gif"/〉 ), no CxAyHz type of calcium aluminum hydrate is formed after aging for 4 days at 20°C and 95% relative humidity. There is also a densifying effect of acetic acid; the open porosity of set samples left to age for 4 days at 20°C and 95% relative humidity decreases from 35 to 25 vol% when 〈inlineGraphic alt="inline image" href="urn:x-wiley:00027820:JACE00414:JACE_00414_mu19" location="equation/JACE_00414_mu19.gif"/〉 goes from 0 to 0.005 and remains relatively constant afterwards. Lastly, this decrease in the porosity continues with aging time; at 6 months, we obtain values as low as 9 vol% in samples where 〈inlineGraphic alt="inline image" href="urn:x-wiley:00027820:JACE00414:JACE_00414_mu20" location="equation/JACE_00414_mu20.gif"/〉.

Notes: Bacterivorous protozoa and bacteria have been in co-existence since the origin of life. This co-existence has led unequivocally to the evolution of many different co-interactions. Most bacteria are ingested and digested, but many escape ingestion for various reasons. Others are ingested but evade digestion, and a few, notoriously Legionella pneumophila, even have the capacity of multiplying within the protozoan host. The aims of this study were to elucidate the interactions of various multi-drug-resistant Staphylococcus aureus (MRSA) strains, Listeria monocytogenes sv4b, and Escherichia coli K12 with the amoeba, Acanthamoeba polyphaga. To evaluate the interactions, we set up co-cultures in Neffs' amoebic saline, at a multiplicity of invasion (MOI) of 1:100 of amoeba to bacteria, and a temperature of 37°C, although the effects of MOI and temperature were also assessed. Survival of bacteria and amoeba was checked at regular intervals, coupled with microscopy. It was discovered under our test conditions, that E. coli was ingested and digested by A. polyphaga, but in contrast, L. monocytogenes, had the capacity to flourish in the presence of A. polyphaga. We also report, for the first time, that all six MRSA isolates tested, survived and replicated in association with A. polyphaga, in comparison to conditions where amoebae were absent. Indeed, we also have evidence suggesting that increases in MRSA, in the presence of A. polyphaga, may be attributable to intracellular survival and replication. These findings have profound implications for the hospital environment, where Acanthamoeba sp., are also commonly isolated. In conclusion, this study illustrates the significance of protozoa as vehicles augmenting the survival of MRSA and L. monocytogenes in the environment.

Notes: The microhabitats favoured by protozoa are dynamic ecosystems comprising a heterogeneous microflora of bacteria and fungi as well as protozoa in a complex biofilm. Many protozoa feed by grazing on microbial biofilms, but they do not do so indiscriminately. A dynamic equilibrium will exist and the nature of the relationship changes depending on environmental conditions. The view of protozoa as the hunter and bacteria as the hunted is now recognised as overly simplistic. Some bacteria not only resist predation by protozoa, but also have become endosymbionts of free-living protozoa, demonstrating adaptation to the otherwise hostile intracellular environment. The concept that protozoa can be reservoirs for some pathogens is more widely appreciated and the catalyst for much of this work came from the observation that Legionella pneumophila infects and multiplies within some species of free-living amoebae. In addition to amplifying cell numbers, the phenotype of intra-protozoal-grown cells is quite distinct from their free-living counterparts cultured on complex laboratory media: altered surface properties, decreased susceptibility to chemical inactivation and antibiotics, and enhanced invasiveness for mammalian cells. There is significant conservation in the genes used by L. pneumophila to parasitize protozoa and macrophages and it has been proposed that co-evolution of bacteria and lower order eukaryotic cells has equipped bacteria both for environmental survival and virulence towards higher order eukaryotes. Other authors have even described protozoa as an “evolutionary gym” enabling L. pneumophila to “train” for its role in invading higher eukaryotic organisms.A growing list of bacteria and fungi that interact with protozoa confirm that the co-evolution between L. pneumophila and protozoa is not unique in nature. An emerging theme amongst many of the micro-organisms associating with protozoa is that they typically are recognised as opportunistic pathogens and many lack a recognised animal host. These features are suggestive of a relationship much closer to symbiosis which becomes parasitic only in special circumstances. The question remains why this is so? The answer could lie in co-evolution with lower order eukaryotic organisms present in biofilms.

Notes: Analysis of medieval luster ceramics seems to indicate that the formation of luster layers could involve an ion exchange between some alkali ions of the glaze (Na+ and K+), and copper and silver cations of the luster raw paint during firing. However, because of the weathering shown by the medieval luster decorations analyzed, conclusive proof is difficult to obtain. A realistic reproduction of the luster decorations has been fabricated in order to follow the process of formation of the luster layer. This has been studied by optical microscopy, transmission electron microscopy, electron probe microanalysis, extended X-ray absorption fine structure, X-ray absorption near-edge structure, and the results give direct evidence that ion exchange and diffusion are the physical–chemical mechanisms responsible for the introduction of copper and silver into the glaze.

Notes: summary  The present study investigated the effectiveness of an intra-oral mandibular advancement device in the treatment of patients with obstructive sleep apnoea (OSA) who could not tolerate or who had failed to comply with continuous positive airway pressure (CPAP). Thirty-five patients diagnosed by sleep study as suffering from OSA, who had either been unable to tolerate or had been non-compliant with CPAP treatment, were included in the study. The subjects completed an Epworth sleep questionnaire. The subjects then had an oral appliance made. After using the appliance for 3 months, the patients repeated the questionnaires and had a repeat sleep study performed with the oral appliance in situ. Thirty-one subjects completed the investigation. Mean AHI pre- and post-study were 26·64 and 24·06, respectively (P 〉 0·05). Mean Epworth scores pre- and post-study were 16·32 and 14·64, respectively (P 〉 0·05). Those patients with a pre-study AHI 〈 20 (n = 23), however, did significantly better with the appliance (P 〈 0·0001). Those patients with a pre-study AHI 〉 20 did not benefit from this device (P 〉 0·05). The main problems encountered were initial jaw discomfort in 18 patients and dry mouth in 11 patients (both of which improved with continued usage). It was concluded that the type of appliance used in this study can be recommended for those with mild OSA who are unable to tolerate CPAP.

Notes: Gastrimmune is an immunogenic form of gastrin. It raises in situ antibodies against two proliferative forms of gastrin: amidated and glycine-extended gastrin-17. It has been shown to have a therapeutic action in several in vivo tumour models. Following immunization, due to the complex equilibrium that exists between the antibodies and gastrin, it is not technically feasible to assay for free gastrin.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To determine the effect of Gastrimmune-induced antigastrin antibodies on acid secretion.〈section xml:id="abs1-3"〉〈title type="main"〉Method:A rat gastric fistula model was used. Animals (six per group) were immunized with a control immunogen or ascending doses of Gastrimmune. Acid output was measured following infusion of increasing doses of gastrin-17 and pentagastrin.〈section xml:id="abs1-4"〉〈title type="main"〉Results:Gastrimmune-induced antibodies significantly reduced gastrin-17-stimulated acid output compared to control animals (Gastrimmune at 200 μg/rat vs. control; acid output following 30 ng gastrin-17, 0.01 vs. 0.16, P 〈 0.001; following 120 ng gastrin-17, 0.022 vs. 0.29, P 〈 0.001).〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:Gastrimmune significantly inhibits gastrin-17-stimulated acid output. This biological assay suggests that the antigastrin antibodies effectively bind gastrin-17. In addition to its use as an antineoplastic agent, Gastrimmune may have a role as an acid-decreasing agent in oesophagogastric pathology.