Surface plasmon resonance imaging detection of silver nanoparticle-tagged immunoglobulin

This article is available open access through the publisher’s website at the link below. Copyright @ 2011 The Royal Society.The detection sensitivity of silver nanoparticle (AgNP)-tagged goat immunoglobulin G (gIgG) microarrays was investigated by studying surface plasmon resonance (SPR) images captured in the visible wavelength range with the help of a Kretchmann-configured optical coupling set-up. The functionalization of anti-gIgG molecules on the AgNP surface was studied using transmission electron microscopy, photon correlation measurements and UV–visible absorption spectroscopy. A value of 1.3 × 107 M−1 was obtained for the antibody–antigen binding constant by monitoring the binding events at a particular resonance wavelength. The detection limit of this SPR imaging instrument is 6.66 nM of gIgG achieved through signal enhancement by a factor of larger than 4 owing to nanoparticle tagging with the antibody.The European Commissio

Implications of a Chr7q21.11 Microdeletion and the Role of the PCLO Gene in Developmental Delay

We report here a 4-year-old boy with global developmental delay who was referred for karyotyping and fragile X studies. A small interstitial deletion on chromosome 7 at band 7q21 was detected in all cells examined. Subsequent molecular karyotype analysis gave the more detailed result of a 6.3 Mb heterozygous deletion involving the interstitial chromosome region 7q21.11. In this relatively gene-poor region, the presynaptic cytomatrix protein, Piccolo (PCLO) gene appears to be the most likely candidate for copy number loss leading to a clinical phenotype. G-banded chromosome analysis of the parents showed this deletion was inherited from the father. Molecular karyotype analysis of the father’s genome confirmed that it was the same deletion as that seen in the son; however, the father did not share the severity of his son’s phenotype. This cytogenetically-visible deletion may represent another example of a chromosomal rearrangement conferring a variable phenotype on different family members

Structure and morphology of ACEL ZnS:Cu,Cl phosphor powder etched by hydrochloric acid

© The Electrochemical Society, Inc. 2009. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version is available at the link below.Despite many researches over the last half century, the mechanism of ac powder electroluminescence remains to be fully elucidated and, to this end, a better understanding of the relatively complex structure of alternate current electroluminescence (ACEL) phosphors is required. Consequently, the structure and morphology of ZnS:Cu,Cl phosphor powders have been investigated herein by means of scanning electron microscopy (SEM) on hydrochloric acid-etched samples and X-ray powder diffraction. The latter technique confirmed that, as a result of two-stage firing during their synthesis, the phosphors were converted from the high temperature hexagonal (wurtzite) structure to the low temperature cubic (sphalerite) polymorph having a high density of planar stacking faults. Optical microscopy revealed that the crystal habit of the phosphor had the appearance of the hexagonal polymorph, which can be explained by the sphalerite pseudomorphing of the earlier wurtzite after undergoing the hexagonal to cubic phase transformation during the synthesis. SEM micrographs of the hydrochloric-etched phosphor particles revealed etch pits, a high density of planar stacking faults along the cubic [111] axis, and the pyramids on the (111) face. These observations were consistent with unidirectional crystal growth originating from the face showing the pyramids.EPSRC, DTI, and the Technology Strategy Board-led Technology Program

Tryptophan Depletion Promotes Habitual over Goal-Directed Control of Appetitive Responding in Humans.

BACKGROUND: Optimal behavioral performance results from a balance between goal-directed and habitual systems of behavioral control, which are modulated by ascending monoaminergic projections. While the role of the dopaminergic system in behavioral control has been recently addressed, the extent to which changes in global serotonin neurotransmission could influence these 2 systems is still poorly understood. METHODS: We employed the dietary acute tryptophan depletion procedure to reduce serotonin neurotransmission in 18 healthy volunteers and 18 matched controls. We used a 3-stage instrumental learning paradigm that includes an initial instrumental learning stage, a subsequent outcome-devaluation test, and a slip-of-action stage, which directly tests the balance between hypothetical goal-directed and habitual systems. We also employed a separate response inhibition control test to assess the behavioral specificity of the results. RESULTS: Acute tryptophan depletion produced a shift of behavioral performance towards habitual responding as indexed by performance on the slip-of-action test. Moreover, greater habitual responding in the acute tryptophan depletion group was predicted by a steeper decline in plasma tryptophan levels. In contrast, acute tryptophan depletion left intact the ability to use discriminative stimuli to guide instrumental choice as indexed by the instrumental learning stage and did not impair inhibitory response control. CONCLUSIONS: The major implication of this study is that serotonin modulates the balance between goal-directed and stimulus-response habitual systems of behavioral control. Our findings thus imply that diminished serotonin neurotransmission shifts behavioral control towards habitual responding.This work was supported by a Wellcome Trust programme grant to T.W.R. (089589/z/09/z). The Behavioral and Clinical Neuroscience Institute is jointly funded by the MRC and the Wellcome Trust (G00001354).This is the final version of the article. It first appeared from Oxford University Press via http://dx.doi.org/10.1093/ijnp/pyv01

A novel method for the preparation of non-agglomerated nanometre sized particles of lanthanum phosphate phosphors utilising a high surface area support in the firing process

This journal is © The Royal Society of Chemistry 2012A convenient method is described that uses a quartz wool substrate to immobilise nanometre sized phosphor precursor particles enabling them to be fired at high temperature without sintering/agglomeration. The nanometre sized phosphor particles are easily removed from the substrate by re-dispersion into liquid for subsequent use.Biotechnology and biological sciences research council (BBSRC

Controlling crystallization and its absence: Proteins, colloids and patchy models

The ability to control the crystallization behaviour (including its absence) of particles, be they biomolecules such as globular proteins, inorganic colloids, nanoparticles, or metal atoms in an alloy, is of both fundamental and technological importance. Much can be learnt from the exquisite control that biological systems exert over the behaviour of proteins, where protein crystallization and aggregation are generally suppressed, but where in particular instances complex crystalline assemblies can be formed that have a functional purpose. We also explore the insights that can be obtained from computational modelling, focussing on the subtle interplay between the interparticle interactions, the preferred local order and the resulting crystallization kinetics. In particular, we highlight the role played by ``frustration'', where there is an incompatibility between the preferred local order and the global crystalline order, using examples from atomic glass formers and model anisotropic particles.Comment: 11 pages, 7 figure

Multicolour correlative imaging using phosphor probes

Correlative light and electron microscopy exploits the advantages of optical methods, such as multicolour probes and their use in hydrated live biological samples, to locate functional units, which are then correlated with structural details that can be revealed by the superior resolution of electron microscopes. One difficulty is locating the area imaged by the electron beam in the much larger optical field of view. Multifunctional probes that can be imaged in both modalities and thus register the two images are required. Phosphor materials give cathodoluminescence (CL) optical emissions under electron excitation. Lanthanum phosphate containing thulium or terbium or europium emits narrow bands in the blue, green and red regions of the CL spectrum; they may be synthesised with very uniform-sized crystals in the 10- to 50-nm range. Such crystals can be imaged by CL in the electron microscope, at resolutions limited by the particle size, and with colour discrimination to identify different probes. These materials also give emissions in the optical microscope, by multiphoton excitation. They have been deposited on the surface of glioblastoma cells and imaged by CL. Gadolinium oxysulphide doped with terbium emits green photons by either ultraviolet or electron excitation. Sixty-nanometre crystals of this phosphor have been imaged in the atmospheric scanning electron microscope (JEOL ClairScope). This probe and microscope combination allow correlative imaging in hydrated samples. Phosphor probes should prove to be very useful in correlative light and electron microscopy, as fiducial markers to assist in image registration, and in high/super resolution imaging studies

Comparison of Ictalurid Hybrid Crosses (Ictalurus punctatus x Ictalurus furcatus) in Floating In-Pond Raceway Systems

Abstract With the US catfish industry facing higher feed costs and stiff international competition, producers are beginning to adopt intensive alternatives to traditional pond culture. Among these are split pond systems and in-pond raceways which offer the ability to produce higher fish biomasses in more stable environmental conditions. The selective pressures of intensive systems necessitate, however, increased attention to identification of genetic strains and crosses of catfish best suited for survival and growth in this dense, competitive environment. Hybrid catfish (Ictalurus punctatus ♀ x Ictalurus furcatus ♂) have demonstrated aggressive feeding behavior and disease resistance characteristics which recommend them for use in intensive systems. However, considerable variability exists in performance among hybrid crosses due to their differing domestication histories and selection strategies carried out on their parental lines. Therefore, here I examined the performance of three hybrid catfish crosses when raised from fry to stocker size fish in intensive systems. Eight hybrid catfish crosses were originally stocked as fry into recirculating aquaculture tanks (RAS) and raised to 6-inch fingerlings. Due to disease susceptibility and/or poor growth observed in five of the crosses, only three hybrid crosses, JSS x D&B, JS x D&B, and KSS x D&B, were then carried forward for the main part of the study. For this study, floating in-pond raceways (FIPRS) were designed and built to improve upon traditional pond culture by offering reduced manpower, higher stocking densities, ease of feeding, grading and complete harvest, and precise disease treatment. The three hybrid crosses were stocked into 12 FIPRS with 4 replicate cells/cross. Fingerlings were grown to stocker size fish and production factors were compared including growth, weight gain, feed conversion ratio iii (FCR), and survival. Length weight regressions were constructed for each of the three crosses for size and weight comparisons and to examine uniformity of growth. From these comparisons, it was determined that there were no significant differences among production per cell, FCR, or survival among the three tested crosses. FCR values averaged 1.4 among the three crosses and survival averaged 92%. Our results indicated that a) D&B blue crosses may produce a more robust hybrid catfish for intensive production, although these results need additional replication and b) early selection for superior performance in intensive systems during the fry to fingerling stage may help to ensure even, predictable production in later stages of grow-out. . Although these experiments were run at a research scale, enterprise budgets (both actual and scenarios at production scale) were developed for each of the three hybrid crosses to analyze the economic feasibility of FIPRS production using selected genetic lines. From these budgets it was determined that a majority of the production cost for these systems come from electricity cost and feed. Due to higher electrical costs, producers would need to carefully match up blower usage with biomass needs, avoid overwintering, and maximize stocking density in order to ensure profitable production. giving us the space needed for design and construction of the raceways and for all their help in the building and moving process. We could not have done much without them. I would also like to thank all the people that were a part of the raceway building and management crew: Esa

A.C.Electroluminescent Lamps: Shedding some light on their mysteries

A.C.powder electroluminescent lamps have been known and used for many years, but their mechanism of operation is still debated. Many thousands of phosphors are known, but the vast majority are not electroluminescent. A number of materials do exhibit the effect. Of these, however, ZnS doped with Cu is absolutely in a class of its own, and is the only material from which viable lamps can be made. In this work studies have been made of the performance of devices under a range of pulsed and continuous excitation conditions and new hypotheses presented which attempt to explain the behavior of this unique material

First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto- noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far