Novel anti-inflammatory compound SEN1176 alleviates behavioural deficits induced following bilateral intrahippocampal injection of aggregated amyloid-beta(1-42).

Behavioral effects of a novel anti-inflammatory SEN1176 were investigated. This pyrrolo[3,2-e][1,2,4]triazolo[1,5-a]pyrimidine suppresses amyloid-ß (Aß)1-42-induced macrophage production of nitric oxide, TNF-a, IL-1ß, and IL-6 in a dose-dependent fashion, an activity profile consistent with SEN1176 being a neuroinflammation inhibitor. Using male Sprague-Dawley rats, SEN1176 was examined relative to detrimental behavioral effects induced following bilateral intrahippocampal (IH) injections of aggregated Aß1-42. The rats were trained to respond under an alternating-lever cyclic-ratio (ALCR) schedule of food reinforcement, enabling measurement of parameters of operant performance that reflect aspects of learning and memory. Under the ALCR schedule, orally administered SEN1176 at 5, 20, or 30 mg/kg was effective in reducing the behavioral deficit caused by bilateral IH aggregated Aß1-42 injections in a dose-related manner over a 90-day treatment period. SEN1176 at 20 and 30 mg/kg significantly reduced lever switching errors and, at doses of 5, 10, and 30 mg/kg, significantly reduced incorrect lever perseverations, indicating a reduction of the behavioral deficit induced as a result of inflammation following IH Aß1-42 injections. When treatment with SEN1176 was instigated 30 days after IH Aß1-42 injections, it resulted in progressive protection, and withdrawal of SEN1176 treatment 60 days after IH Aß1-42 injections revealed partial retention of the protective effect. SEN1176 also significantly reduced numbers of activated astrocytes adjacent to the aggregated Aß1-42 injection sites. These results indicate the potential of SEN1176 for alleviating chronic neuroinflammatory processes related to brain Aß deposition that affect learning and memory in Alzheimer's disease.

Liquid-liquid slug flow: Hydrodynamics and pressure drop

In this paper, the hydrodynamics and the pressure drop of liquid-liquid slug flow in round microcapillaries are presented. Two liquid-liquid flow systems are considered, viz. water-toluene and ethylene glycol/water-toluene. The slug lengths of the alternating continuous and dispersed phases were measured as a function of the slug velocity (0.03-0.5 m/s), the organic-to-aqueous flow ratio (0.1-4.0), and the microcapillary internal diameter (248 and 498 mu m). The pressure drop is modeled as the sum of two contributions: the frictional and the interface pressure drop. Two models are presented, viz, the stagnant film model and the moving film model. Both models account for the presence of a thin liquid film between the dispersed phase slug and the capillary wall. It is found that the film velocity is of negligible influence on the pressure drop. Therefore, the stagnant film model is adequate to accurately predict the liquid-liquid slug flow pressure drop. The influence of inertia and the consequent change of the slug cap curvature are accounted for by modifying Bretherton's curvature parameter in the interface pressure drop equation. The stagnant film model is in good agreement with experimental data with a mean relative error of less than 7%.

Controlling the response characteristics of luminescent porphyrin plastic film sensors for oxygen

Two porphyrins, platinum(II) octaethylporphyrin (Pt-OEP) and palladium(II) octaethylporphyrin (Pd-OEP), are incorporated into a wide variety of different encapsulating matricies and tested as oxygen sensors, The excited state lifetimes of the two porphyrins are quite different, 0.091 ms for Pt-OEP and 0.99 ms for Pd-OEP, and Pt-OEP-based oxygen sensors are found to be much less sensitive than Pd-OEP-based ones to quenching by oxygen, Two major response characteristics of an oxygen sensor are (i) its sensitivity toward oxygen and (ii) its response and recovery times when exposed to an alternating atmosphere of nitrogen and air. The response characteristics of a rang of Pt-OEP, and Pd-OEP-based oxygen sensors were determined using cellulose acetate butyrate (CAB), poly(methyl methacrylate) (PMMA), and PMMA/CAB polymer blends as the encapsulating media. Pt-OEP and Pd-OEP oxygen sensors have better response characteristics (i.e., more sensitive and lower response and recovery times) when CAB is used as the encapsulating medium rather than PMMA. For both Pt-OEP- and Pd-OEP-based oxygen sensors, in either polymer, increasing the level of tributyl phosphate plasticizer improves the response characteristics of the final oxygen-sensitive film. Pt-OEP in different unplasticized PMMA/CAB blended films produced a range of oxygen sensors in which the response characteristics improved with increasing level of CAB present.

Fluorescence-based thin plastic film ion-pair sensors for oxygen

A general method of preparation of thin-film sensors for O-2, incorporating the dye ion-pair tris(4,7-diphenyl-1,10-phenanthroline) rutheninm(II) ditetraphenylborate, in a variety of different thin film polymer/plasticizer matrices is described, The sensitivity of the sensor depends upon the nature of the polymer matrix and plasticizer, A detailed study of one of these systems utilising the polymer poly(methyl methacrylate), PMMA, is reported. The sensitivity of this O-2 sensor depends markedly upon the plasticizer concentration and is largely independent of temperature (24,5-52.5 degrees C) and age (up to 30 d), When exposed to an alternating atmosphere of O-2 and N-2, a typical oxygen film sensor in PMMA exhibits a 0-90% response and recovery time of 0.4 and 4.5 s, respectively.

Thin plastic film colorimetric sensors for carbon dioxide: Effect of plasticizer on response

Different plasticizers, including phosphate-, phthalate-and adipate-based types were used in the creation of a range of colorimetric plastic film sensors for CO2, The different types of plasticizer used in the formulation of a colorimetric plastic film sensor for CO2 affect the response and recovery times of the sensor differently, An effective plasticizer was taken as one that decreased the response and recovery times of the final film sensor when exposed to an alternating atmosphere of 0-5% CO2. On this basis, the most efficient plasticizers appeared to be phosphate-based, followed by phthalate- and adipate-based plasticizers, This trend appears to reflect the degree of the polymer-plasticizer compatibility. Increasing the amount of plasticizer in the film formulation decreased the response and recovery times of the sensor dramatically, The sensitivity of the film sensor towards CO2 appears to decrease with increasing plasticizer effectiveness; thus, the general order of film CO2 sensitivity with respect to plasticizer type was found to be adipate > phthalate > phosphate. In general, the response of the optical films towards CO2 was found to be temperature sensitive [typically, Delta H = -(44-55) kJ mol(-1)], The phosphate-based plasticized films appear to be less temperature sensitive than the other plasticized films, and 2-ethylhexyl diphenylphosphate appears particularly effective in this respect (Delta H = -18.5 kJ mol(-1)).

FLUORESCENCE PLASTIC THIN-FILM SENSOR FOR CARBON-DIOXIDE

The method of preparation of a novel plastic thin-film sensor that incorporates the fluorescent dye 8-hydroxypryrene-1,3,6-trisulfonic acid is described; the shelf-life of the film is over 6 months. The results of a study on the equilibrium response of the sensor towards different levels of gaseous CO2 fit a model there is a 1 + 1 equilibrium reaction between the deprotonated form of the dye (present in the film as an ion pair) and the concentration of gaseous CO2 present. In contrast to the situation in aqueous solution, in the plastic film the pK(a) of the excited form of the dye appears close to that of the ground-state form, although this does not interfere with its use as 8 CO2 sensor. The 0 to 90% response and recovery times of the film when exposed to an alternating atmosphere of air and 5% CO2 are typically 4.3 and 7.1 s, respectively.

EQUILIBRIUM STUDIES ON COLORIMETRIC PLASTIC FILM SENSORS FOR CARBON-DIOXIDE

The equilibrium responses of three new colorimetric plastic film sensors for CO2 as a function of % CO2 and temperature are described. The results fit a model in which there is a 1:1 equilibrium reaction between the deprotonated form of the dye (present in the film as an ion pair) and CO2. The 0-50% and 0-90% response and recovery times of each of these films when exposed to an alternating atmosphere of air and 5% CO2 are determined and in two cases are typically less than 3 s. The shelf life of the films is long (many months); however, prolonged use of the films leads to the permanent generation of the protonated form of the dye over a period of 20-100 h. A possible cause of this latter effect is discussed.

Coherent Control of High Harmonic Generation via Dual-Gas Multijet Arrays

High harmonic generation (HHG) is a central driver of the rapidly growing field of ultrafast science. We present a novel quasiphase-matching (QPM) concept with a dual-gas multijet target leading, for the first time, to remarkable phase control between multiple HHG sources (> 2) within the Rayleigh range. The alternating jet structure with driving and matching zones shows perfect coherent buildup for up to six QPM periods. Although not in the focus of the proof-of-principle studies presented here, we achieved competitive conversion efficiencies already in this early stage of development.

Reappraisal of the type species of Polysiphonia (Rhodomelaceae, Rhodophyta)

The genus Polysiphonia Greville, nom. cons., has had a long and confused nomenclatural history. At present, Polysiphonia has a wide circumscription, including at least 200 species, but it is heterogeneous in many vegetative and reproductive developmental features. Central to any re-evaluation of the genus is a detailed examination of the type species of Polysiphonia, P. urceolata (Lightfoot ex Dillwyn) Greville, which is conspecific with P. stricta (Dillwyn) Greville. We here report on the vegetative and reproductive morphology of P. stricta, including P, urceolata, based on type and other material from the British Isles. Thalli consist of prostrate and erect ecorticate axes with four pericentral cells, attached by unicellular rhizoids remaining in open connection with pericentral cells. Prostrate axes lack vegetative trichoblasts; trichoblasts occur seasonally on erect axes. Branch initials are cut off from the subapical cell at intervals of four or five segments in dichotomous and alternating pairs rather than being formed horn each axial cell in the spiral pattern typical of most species of Polysiphonia. Spermatangial branch initials, which are trichoblast homologues, are produced directly from each axial cell at the tips of erect branches, not subtended by trichoblasts, and have two- to five-celled sterile tips when mature. The mature carpogonial branch is four-celled with a two-celled first sterile group and a one-celled second sterile group. Following presumed fertilization, direct fusion apparently takes place between carpogonium and auxiliary tell; mature cystocarps are usually urceolate. Tetrasporangia are formed from the third pericentral cell, in straight series, and have two pre-sporangial cover cells. Previous accounts of a third, post-sporangial cover cell could not be substantiated. P. stricta and a small group of other Polysiphonia species differ in several important respects from most members of the genus, which have rhizoids cut off from pericentral cells by a cell division, abundant trichoblasts, spirally arranged tetrasporangia and a post-sporangial cover cell. The branching pattern of P. stricta highlights the difficulties of distinguishing between the tribes Polysiphonieae and Pterosiphonieae.

Abeta oligomer toxicity inhibitor protects memory in models of synaptic toxicity

BACKGROUND AND PURPOSE:

Amyloid-ß (Aß) aggregation into synaptotoxic, prefibrillar oligomers is a major pathogenic event underlying the neuropathology of Alzheimer's disease (AD). The pharmacological and neuroprotective properties of a novel Aß aggregation inhibitor, SEN1269, were investigated on aggregation and cell viability and in test systems relevant to synaptic function and memory, using both synthetic Aß(1-42) and cell-derived Aß oligomers.
EXPERIMENTAL APPROACH:

Surface plasmon resonance studies measured binding of SEN1269 to Aß(1-42) . Thioflavin-T fluorescence and MTT assays were used to measure its ability to block Aß(1-42) -induced aggregation and reduction in cell viability. In vitro and in vivo long-term potentiation (LTP) experiments measured the effect of SEN1269 on deficits induced by synthetic Aß(1-42) and cell-derived Aß oligomers. Following i.c.v. administration of the latter, a complex (alternating-lever cyclic ratio) schedule of operant responding measured effects on memory in freely moving rats.
KEY RESULTS:

SEN1269 demonstrated direct binding to monomeric Aß(1-42) , produced a concentration-related blockade of Aß(1-42) aggregation and protected neuronal cell lines exposed to Aß(1-42) . In vitro, SEN1269 alleviated deficits in hippocampal LTP induced by Aß(1-42) and cell-derived Aß oligomers. In vivo, SEN1269 reduced the deficits in LTP and memory induced by i.c.v. administration of cell-derived Aß oligomers.
CONCLUSIONS AND IMPLICATIONS:

SEN1269 protected cells exposed to Aß(1-42) , displayed central activity with respect to reducing Aß-induced neurotoxicity and was neuroprotective in electrophysiological and behavioural models of memory relevant to Aß-induced neurodegeneration. It represents a promising lead for designing inhibitors of Aß-mediated synaptic toxicity as potential neuroprotective agents for treating AD.

Multiple self-aligned iron nanowires by a dual selective chemical vapor deposition process

We have demonstrated a self-aligned process to fabricate organized iron nanowires on a planarized surface with wire dimensions down to 50 nm. Polishing was used to expose an alternating silicon silicon dioxide edge and a dual selective metal deposition process produced the nanowires. The initial selective deposition produced a tungsten layer on the exposed polysilicon regions. The discovery that selective chemical vapor deposition of iron from Fe(CO)(5) precursor on dielectric surfaces over tungsten surfaces is the key factor that enables the self-alignment of the iron nanowires. Dimensions of the wires are determined by the thickness of the thermal oxide. (c) 2007 The Electrochemical Society.

Dynamics of a dust crystal with positive and negative dust

A dust crystal consisting of charged dust grains of alternating charge sign (.../+/-/+/-/+/...) and mass is considered. Considering the equations of longitudinal motion, a linear dispersion relation is derived from first principles, and then analyzed. Two modes are obtained, including an acoustic mode and an inverse-dispersive optic-like one. The nonlinear aspects of longitudinal dust grain motion are also briefly addressed, via a Boussineq and Korteweg- de Vries description.

The dynamics of arsenic in four paddy fields in the Bengal delta

Irrigation with arsenic contaminated groundwater in the Bengal Delta may lead to As accumulation in the soil and rice grain. The dynamics of As concentration and speciation in paddy fields during dry season (boro) rice cultivation were investigated at 4 sites in Bangladesh and West Bengal, India. Three sites which were irrigated with high As groundwater had elevated As concentrations in the soils, showing a significant gradient from the irrigation inlet across the field. Arsenic concentration and speciation in soil pore water varied temporally and spatially; higher As concentrations were associated with an increasing percentage of arsenite, indicating a reductive mobilization. Concentrations of As in rice grain varied by 2-7 fold within individual fields and were poorly related with the soil As concentration. A field site employing alternating flooded-dry irrigation produced the lowest range of grain As concentration, suggesting a lower soil As availability caused by periodic aerobic conditions.

Multilayer mirrored bubbles with spatially-chirped and elastically-tuneable optical bandgaps

We demonstrate the multifolding Origami manufacture of elastically-deformable Distributed Bragg Reflector (DBR) membranes that reversibly color-tune across the full visible spectrum without compromising their peak reflectance. Multilayer films composed of alternating transparent rubbers are fixed over a 300 mu m wide pinhole and deformed by pressure into a concave shape. Pressure-induced color tuning from the near-IR to the blue arises from both changes in thickness of the constituent layers and from tilting of the curved DBR surfaces. The layer thickness and color distribution upon deformation, the band-gap variation and the repeatability of cyclic color tuning, are mapped through micro-spectroscopy. Such spatially-dependent thinning of the film under elastic deformation produces spatial chirps in the color, and are shown to allow reconstruction of complex 3D strain distributions. (C) 2012 Optical Society of America

Hermit crabs perceive the extent of their virtual bodies

A flexible body image is required by animals if they are to adapt to body changes and move effectively within a structurally complex environment. Here, we show that terrestrial hermit crabs, Coenobita rugosus, which frequently change shells, can modify walking behaviour, dependent on the shape of the shell. Hermit crabs walked along a corridor that had alternating left and right corners; if it was narrow at the corner, crabs rotated their bodies to avoid the wall, indicating an awareness of environmental obstacles. This rotation increased when a plastic plate was attached to the shell. We suggest that the shell, when extended by the plate, becomes assimilated to the hermit crab's own body. While there are cases of a tool being assimilated with the body, our result is the first example of the habitat where an animal lives and/or carries being part of a virtual body. This journal is © 2012 The Royal Society.