Method for separating biological cells

A method for separating biological cells by suspending a mixed cell population in a two-phase polymer system is described. The polymer system consists of droplet phases with different surface potentials for which the cell populations exhibit different affinities. The system is subjected to an electrostatic field of sufficient intensity to cause migration of the droplets with an attendant separation of cells

Standard arc welders provide high amperage direct current source

Standard arc welders or power supplies are hooked up in parallel or series connections to obtain an adequate supply of current or voltage for various purposes. This method provides maximum flexibility in a wide range of voltages and currents

Cell partition in two phase polymer systems

Aqueous phase-separated polymer solutions can be used as support media for the partition of biological macromolecules, organelles and cells. Cell separations using the technique have proven to be extremely sensitive to cell surface properties but application of the systems are limited to cells or aggregates which do not significantly while the phases are settling. Partition in zero g in principle removes this limitation but an external driving force must be applied to induce the phases to separate since their density difference disappears. We have recently shown that an applied electric field can supply the necessary driving force. We are proposing to utilize the NASA FES to study field-driven phase separation and cell partition on the ground and in zero g to help define the separation/partition process, with the ultimate goal being to develop partition as a zero g cell separation technique

Countercurrent distribution of biological cells

A neutral polymer phase system consisting of 7.5 percent dextran 40/4.5 percent PEG 6, 0.11 M Na phosphate, 5 percent fetal bovine serum (FBS), pH 7.5, was developed which has a high phase droplet electrophoretic mobility and retains cell viability over many hours. In this and related systems, the drop mobility was a linear function of drop size, at least in the range 4-30 micron diameter. Applications of and electric field of 4.5 v/cm to a system containing 10 percent v/v bottom phase cleared the system more than two orders of magnitude faster than in the absence of the field. At higher bottom phase concentrations a secondary phenomenon intervened in the field driven separations which resulted in an increase in turbidity after clearing had commenced. The increase was associated with a dilution of the phase system in the chamber. The effect depended on the presence of the electric field. It may be due to electroosmotic flow of buffer through the Amicon membranes into the sample chamber and flow of phase system out into the rinse stream. Strategies to eliminate this problem are proposed

SPAR project: Counter current distribution of biologicals

Preliminary ground based experiments strongly support the validity of a proposed space experiment in the separation of biological cells by counter current distribution (CCD). It was shown that a low level applied selective field can accelerate the separation of the phases by a very large factor. An electric field therefore should be very effective in space in lieu of gravity for the phase separation step. This appears to solve a central problem in implementing CCD in space and opens the technique to many types of large cell mixtures for which it has not been applicable before due to rapid settling effects. It was determined that electrophoretic migration of the cells, as a possibly disturbing factor, will be of negligible effect. Attenuation of a light beam by scattering generated a signal indicating the course of the phase separation

Harry Potter and metaphysical hospitality

Continuing the series of investigations of hospitality practices in different locations, Kevin O'Gorman and David Brooks explore what muggles can learn from the hospitality experienced in the world of wizardry. These epic fantasies have some mind-expanding messages for those who will listen

Mathematical Properties of a Class of Four-dimensional Neutral Signature Metrics

While the Lorenzian and Riemanian metrics for which all polynomial scalar curvature invariants vanish (the VSI property) are well-studied, less is known about the four-dimensional neutral signature metrics with the VSI property. Recently it was shown that the neutral signature metrics belong to two distinct subclasses: the Walker and Kundt metrics. In this paper we have chosen an example from each of the two subcases of the Ricci-flat VSI Walker metrics respectively. To investigate the difference between the metrics we determine the existence of a null, geodesic, expansion-free, shear-free and vorticity-free vector, and classify these spaces using their infinitesimal holonomy algebras. The geometric implications of the holonomy algebras are further studied by identifying the recurrent or covariantly constant null vectors, whose existence is required by the holonomy structure in each example. We conclude the paper with a simple example of the equivalence algorithm for these pseudo-Riemannian manifolds, which is the only approach to classification that provides all necessary information to determine equivalence.Comment: 18 page

Systematic Review of Physiotherapy during Acute Exacerbations of Chronic Obstructive Pulmonary Disease (AECOPD)

In COPD patients, acute exacerbations are important events. Reviews of studies investigating treatment during AECOPD focus on medical management, with little discussion of physiotherapy. Therefore a systematic review was undertaken of the studies pertaining to physiotherapy during AECOPD. Methods: Studies were identified by searching databases and scanning reference lists. Appropriate studies were reviewed by two independent investigators. Data were extracted using a standardized form. Where possible, a score was assigned using the PEDro scale for assessment of study quality. HIll, K., Patman, S., & Brooks, D. (2008). Systematic review of physiotherapy during Acute Exacerbations of Chronic Obstructive Pulmonary Disease (AECOPD). American Journal of Respiratory and Critical Care Medicine, 177, Abstracts Issue, A137. ISSN: 1073-449

Flexible ring slosh damping baffle Patent

Flexible ring slosh damping baffle for spacecraft fuel tan

Adapting structuration theory to understand the role of reflexivity: Problematization, clinical audit and information systems

This paper is an exploratory account of the further development and application of a hybrid framework, StructurANTion, that is based on Structuration Theory and Actor Network Theory (ANT). The use of social theories in general and their use in information systems (IS) research in particular is explored leading to the use of the framework to examine the concept of what are termed humanchine networks in the context of clinical audit, within a healthcare Primary Care Trust (PCT). A particular focus is on the manner in which information systems-based reflexivity contributes to both entrenching a networks’ structurated order as well as contributing to its emancipatory change. The case study compares clinic-centric and patientcentric audit and seeks to further extend the understanding of the role of information and information systems within structurated humanchine activity systems. Conclusions indicate that the use of more socially informed IS methods and approaches can incorporate more emancipatory ideals and lead to greater adoption and usage of more relevant and useful clinical information systems and practices