Lanthanide-based time-resolved luminescence immunoassays

The sensitive and specific detection of analytes such as proteins in biological samples is critical for a variety of applications, for example disease diagnosis. In immunoassays a signal in response to the concentration of analyte present is generated by use of antibodies labeled with radioisotopes, luminophores, or enzymes. All immunoassays suffer to some extent from the problem of the background signal observed in the absence of analyte, which limits the sensitivity and dynamic range that can be achieved. This is especially the case for homogeneous immunoassays and surface measurements on tissue sections and membranes, which typically have a high background because of sample autofluorescence. One way of minimizing background in immunoassays involves the use of lanthanide chelate labels. Luminescent lanthanide complexes have exceedingly long-lived luminescence in comparison with conventional fluorophores, enabling the short-lived background interferences to be removed via time-gated acquisition and delivering greater assay sensitivity and a broader dynamic range. This review highlights the potential of using lanthanide luminescence to design sensitive and specific immunoassays. Techniques for labeling biomolecules with lanthanide chelate tags are discussed, with aspects of chelate design. Microtitre plate-based heterogeneous and homogeneous assays are reviewed and compared in terms of sensitivity, dynamic range, and convenience. The great potential of surface-based time-resolved imaging techniques for biomolecules on gels, membranes, and tissue sections using lanthanide tracers in proteomics applications is also emphasized

Delivering stepped care: an analysis of implementation in routine practice

addresses: Mood Disorders Centre, University of Exeter, Exeter, EX4 4QG, UK. [email protected]: PMCID: PMC3283464types: Journal Article; Multicenter Study; Research Support, Non-U.S. Gov't© 2012 Richards et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.In the United Kingdom, clinical guidelines recommend that services for depression and anxiety should be structured around a stepped care model, where patients receive treatment at different 'steps,' with the intensity of treatment (i.e., the amount and type) increasing at each step if they fail to benefit at previous steps. There are very limited data available on the implementation of this model, particularly on the intensity of psychological treatment at each step. Our objective was to describe patient pathways through stepped care services and the impact of this on patient flow and management

Experimental results from the ST7 mission on LISA Pathfinder

The Space Technology 7 Disturbance Reduction System (ST7-DRS) is a NASA technology demonstration payload that operated from January 2016 through July 2017 on the European Space Agency’s (ESA) LISA Pathfinder spacecraft. The joint goal of the NASA and ESA missions was to validate key technologies for a future space-based gravitational wave observatory targeting the source-rich millihertz band. The two primary components of ST7-DRS are a micropropulsion system based on colloidal micro-Newton thrusters (CMNTs) and a control system that simultaneously controls the attitude and position of the spacecraft and the two free-flying test masses (TMs). This paper presents our main experimental results and summarizes the overall performance of the CMNTs and control laws. We find the CMNT performance to be consistent with preflight predictions, with a measured system thrust noise on the order of 100  nN/√Hz in the 1  mHz≤f≤30  mHz band. The control system maintained the TM-spacecraft separation with an RMS error of less than 2 nm and a noise spectral density of less than 3  nm/√Hz in the same band. Thruster calibration measurements yield thrust values consistent with the performance model and ground-based thrust-stand measurements, to within a few percent. We also report a differential acceleration noise between the two test masses with a spectral density of roughly 3  fm/s2/√Hz in the 1  mHz≤f≤30  mHz band, slightly less than twice as large as the best performance reported with the baseline LISA Pathfinder configuration and below the current requirements for the Laser Interferometer Space Antenna mission

Task-Performance And Electromyopotential As Functions Of Task-Difficulty And Emg Feedback

The dearth of empirical research in the application of biofeedback is discussed. Exp. 1 assessed relationships among biofeedback EMG training, EMG levels, cognitive task performance, and task difficulty. 72 subjects (male or female college students) were administered 1 trial on an iconic memory task with either EMG audio feedback, sham EMG audio feedback, or no feedback. Three levels of task difficulty were used. One 20-min. training session significantly lowered EMG responses, and task performance was inversely related to task difficulty. No relationship between EMG level and task performance was observed. Exp. 2 investigated the effect of increased EMG responses on cognitive task performance for one level of difficulty. One biofeedback training session did not significantly increase frontalis EMG, and there was no relationship between increased EMG and task performance

Assessing peridomestic entomological factors as predictors for Lyme disease

The roles of entomologic risk factors, including density of nymphal blacklegged ticks (Ixodes scapularis), prevalence of nymphal infection with the etiologic agent (Borrelia burgdorferi), and density of infected nymphs, in determining the risk of human Lyme disease were assessed at residences in the endemic community of South Kingstown, RI. Nymphs were sampled between May and July from the wooded edge around 51 and 47 residential properties in 2002 and 2003, respectively. Nymphs were collected from all residences sampled. Tick densities, infection rates, and densities of infected nymphs were all significantly higher around homes reporting Lyme disease histories in 2003, while only infection rates were significantly higher in 2002. However, densities of infected nymphs did not significantly predict the probability of Lyme disease at a residence (by logistic regression) in either year. There were no significant differences in entomologic risk factors between homes with state-confirmed Lyme disease histories and homes with self-reported cases (not reported to the state health department). Therefore, although entomologic risk factors tended to be higher at residences with cases of Lyme disease, entomological indices, in the absence of human behavior measures, were not useful predictors of Lyme disease at the scale of individual residences in a tick-endemic community

Three Recurring Electromyographic Biofeedback Research Problems And A Laboratory Model

Exp. I investigated three recurring problems in electromyographic (EMG) biofeedback research. (1) Pre-knowledge that research involved biofeedback resulted in a selective bias on the part of students asked to volunteer as subjects. (2) EMG readings were not affected by repeated use of the word relax in verbal instructions. (3) The forearm extensor was the only muscle group which showed a statistically significant effect after one 20-min. training session. Exp. II challenged and clarified results of Exp. I and concluded the study with an empirically derived laboratory model for EMG biofeedback research

Time-gated luminescent in situ hybridization (LISH): Highly Sensitive Detection of Pathogenic Staphylococcus aureus

© 2019 by the authors We describe simple direct conjugation of a single TEGylated Europium chelate to DNA that binds to intracellular rRNA and is then detected using a homogeneous luminescent in situ hybridisation (LISH) technique. As a proof-of-principle, Staphylococcus aureus (S. aureus) was selected as a model for our study to show the ability of this probe to bind to intracellular 16S ribosomal rRNA. A highly purified Europium chelate conjugated oligonucleotide probe complementary to an rRNA sequence-specific S. aureus was prepared and found to be soluble and stable in aqueous solution. The probe was able to bind specifically to S. aureus via in situ hybridisation to differentiate S. aureus from a closely related but less pathogenic Staphylococcus species (S. epidermidis). A time-gated luminescent (TGL) microscope system was used to generate the high signal-to-noise ratio (SNR) images of the S. aureus. After excitation (365 nm, Chelate λmax = 335 nm), the long-lived (Eu3+) luminescent emission from the probe was detected without interference from natural background autofluorescence typically seen in biological samples. The luminescent images were found to have 6 times higher SNR or sensitivity compared to the fluorescent images using conventional fluorophore Alexa Fluor 488. The TEGylated Europium chelate -oligo probe stained S. aureus with mean signal intensity 3.5 times higher than the threshold level of signal from S. epidermidis (with SNR 8 times higher). A positive control probe (EUB338–BHHTEGST–Eu3+) has mean signal intensity for S. aureus and S. epidermidis equally 3.2 times higher than the threshold of signal for a negative NON-EUB338 control probe. The direct conjugation of a single Europium chelate to DNA provides simplicity and improvement over existing bovine serum albumin (BSA)/streptavidin/biotinylated DNA platforms for multi-attachment of Europium chelate per DNA and more importantly makes it feasible for hybridisation to intracellular RNA targets. This probe has great potential for highly sensitive homogeneous in situ hybridisation detection of the vast range of intracellular DNA targets