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

Solvation free energy profile of the SCN- ion across the water-1,2-dichloroethane liquid/liquid interface. A computer simulation study

The solvation free energy profile of a single SCN- ion is calculated across the water-1,2-dichloroethane liquid/liquid interface at 298 K by the constraint force method. The obtained results show that the free energy cost of transferring the ion from the aqueous to the organic phase is about 70 kJ/mol, The free energy profile shows a small but clear well at the aqueous side of the interface, in the subsurface region of the water phase, indicating the ability of the SCN- ion to be adsorbed in the close vicinity of the interface. Upon entrance of the SCN- ion to the organic phase a coextraction of the water molecules of its first hydration shell occurs. Accordingly, when it is located at the boundary of the two phases the SCN- ion prefers orientations in which its bulky S atom is located at the aqueous side, and the small N atom, together with its first hydration shell, at the organic side of the interface

Confirmation bias perpetuates century-old ecological misconception: Evidence against \u27Secretive\u27 behavior of Eastern Spadefoots

Despite a 1944 publication questioning the misconception that Eastern Spadefoots (Scaphiopus holbrookii) and other Scaphiopodidae are \u27secretive\u27 outside of rain-induced migration and breeding aggregations, confirmation bias has perpetuated this fallacy. As a result, S. holbrookii is one of the least studied frogs in the United States. Amassing a large postmetamorphic dataset, we examined the misconception that S. holbrookii are secretive outside of breeding aggregates or optimal environmental conditions. Using eyeshine spotlighting, we conducted transect, mark-recapture, and haphazard spotlighting surveys in Virginia and Rhode Island forests. Although no breeding events or migration occurred during this study, we detected thousands of postmetamorphic S. holbrookii in Virginia and dozens in Rhode Island, the majority of which were subadults-a demographic category severely overlooked in the literature. These results are in direct contradiction with historical surveys of our sites. Spotlighting was an efficient method of detecting S. holbrookii eyeshine in forests, which were easily differentiated from arthropod eyeshine. Minimal effort was needed to detect the presence of S. holbrookii in Virginia and Rhode Island, even though both states have different climates and S. holbrookii densities. We also discovered a previously undetected population in Rhode Island. Scaphiopus holbrookii of all postmetamorphic size classes emerged regularly from burrows, even with no precipitation. We discuss how confirmation bias and lack of appropriate field methods for nonbreeding life history stages has fueled the misconception that S. holbrookii are difficult to find outside of optimal weather conditions, which has hindered progress studying the ecology and conservation of this species

“Family Troubles” and “Troubling Families”: Opening Up Fertile Ground

The twin themes of “family troubles” and “troubling families” are closely linked, but they are also each distinct in themselves, and nuanced in particular ways. Rooted particularly (but not solely) in our U.K.-based academic experiences, we offer an account of family studies as siloed between a binary of “the mainstream”, focused on what may be implicitly understood as “ordinary” family lives, and “the problematic”, focused on aspects of family lives that may be of interest to social policy experts, professionals, and practitioners and geared toward interventions of some sort. What has been missing has been sociological attention to the pervasiveness of change and challenges as core for all family lives over time, with such changes sometimes experienced as troubling by family members themselves, and/or seen to be troubling by others such as professionals who saw them as “dysfunctional”, or policy makers who saw them as “social problems”. Practice and policy-oriented research has thus focused on interventions to “make things better”, or to achieve “reforms”, for families that are considered to be “problematic”. Consequently, what may be described as the “normal troubles” of family lives have been largely neglected. In this article, we explore what is brought into view by focusing on “family troubles” and “troubling families”; we argue that these themes offer fertile ground for opening up new dialogue between these contrasting bodies of work, questioning and crossing boundaries, illuminating taken-for-granted assumptions, and encouraging fresh perspectives