QUANTITATION OF HUMAN RED BLOOD CELL FIXATION BY GLUTARALDEHYDE

The uptake of glutaraldehyde by human red blood cells has been measured as a function of time by a freezing point osmometer. The rate of attachment of glutaraldehyde to the cell proteins is high over the first hour, declining to zero over a period of a few days. The number of glutaraldehyde molecules cross-linking with each hemoglobin molecule is of the order of 200, in reasonable agreement with the calculated number of attachment sites. The cell membrane is immediately highly permeable to glutaraldehyde. Selective permeability to ions is lost during fixation. Ionic equilibrium is obtained only after a few hours. An optimum fixation technique for shape preservation is suggested

Echocardiographic abnormalities and disease severity in Fabry's disease

Fabry's disease is an X-linked recessive genetic deficiency of the enzyme alpha-galactosidase A, which leads to the pathologic deposition of neutral glycosphingolipids in lysosomes of the vascular endothelium of the heart, brain and kidney. The disease is progressive in hemizygous male patients, with increasing involvement of the major organs leading to death. Because cardiac involvement is a constant feature, echocardiograms were performed on 35 patients with Fabry's disease, 23 hemizygotes (aged 28.6 ± 14 years) and 12 heterozygotes (aged 31.6 ± 6 years), to determine whether cardiac involvement could be detected noninvasively.The results demonstrated that hemizygous male patients had a greater aortic root diameter, thicker interventricular septum and greater ventricular mass than did heterozygous female patients. Left ventricular mass per square meter of body surface area correlated well with clinical disease severity (r = 0.68, p < 0.05), suggesting progressive glycosphingolipid deposition. Older heterozygotes (>25 years old) had more severe evidence of cardiac disease than did younger male patients. Although mitral valve prolapse was identified in 12 (54%) of 23 male hemizygotes and in 7 (58%) of 12 female heterozygotes, its presence did not correlate with clinical disease severity or other echocardiographic variables. Therefore, echocardiographic evidence of Fabry's disease appears to correlate with age-related disease severity and may be a useful noninvasive marker to follow disease progression and possible regression when appropriate therapy becomes available

Understanding initial data for black hole collisions

Numerical relativity, applied to collisions of black holes, starts with initial data for black holes already in each other's strong field. The initial hypersurface data typically used for computation is based on mathematical simplifying prescriptions, such as conformal flatness of the 3-geometry and longitudinality of the extrinsic curvature. In the case of head on collisions of equal mass holes, there is evidence that such prescriptions work reasonably well, but it is not clear why, or whether this success is more generally valid. Here we study these questions by considering the ``particle limit'' for head on collisions of nonspinning holes. Einstein's equations are linearized in the mass of the small hole, and described by a single gauge invariant spacetime function psi, for each multipole. The resulting equations have been solved by numerical evolution for collisions starting from various initial separations, and the evolution is studied on a sequence of hypersurfaces. In particular, we extract hypersurface data, that is psi and its time derivative, on surfaces of constant background Schwarzschild time. These evolved data can then be compared with ``prescribed'' data, evolved data can be replaced by prescribed data on any hypersurface, and evolved further forward in time, a gauge invariant measure of deviation from conformal flatness can be evaluated, etc. The main findings of this study are: (i) For holes of unequal mass the use of prescribed data on late hypersurfaces is not successful. (ii) The failure is likely due to the inability of the prescribed data to represent the near field of the smaller hole. (iii) The discrepancy in the extrinsic curvature is more important than in the 3-geometry. (iv) The use of the more general conformally flat longitudinal data does not notably improve this picture.Comment: 20 pages, REVTEX, 26 PS figures include

Serologic and Molecular Detection of Granulocytic Ethrlichiosis in Rhode Island

A new indirect fluorescent-antibody (IFA) assay with antigen produced in vitro in the human promyelocytic leukemia cell line HL60 was used to identify the first recognized case of human granulocytic ehrlichiosis in Rhode Island. This IFA assay was used to detect granulocytic ehrlichiae in white-footed mice and in a dog inhabiting the area surrounding the patient’s residence. Host-seeking Ixodes scapularis ticks found in the same habitat also were infected. I. scapularis ticks collected from other locations were fed on dogs and New Zealand White rabbits to assess the competency of these species as hosts of granulocytotropic Ehrlichia. Tick-induced infections of dogs were confirmed by serologic testing, tissue culture isolation, and PCR amplification, whereas several rabbits seroconverted but were PCR and culture negative. PCR amplification of the 16S rRNA gene and DNA sequencing of the PCR products or culture isolation was used to confirm granulocytic Ehrlichia infections in humans, dogs, white-footed mice, and ticks

Wild to domestic and back again: the dynamics of fallow deer management in medieval England (c.11th-16th century AD)

This paper presents the results of the first comprehensive scientific study of the fallow deer, a non-native species whose medieval-period introduction to Britain transformed the cultural landscape. It brings together data from traditional zooarchaeological analyses with those derived from new ageing techniques as well as the results of a programme of radiocarbon dating, multi-element isotope studies and genetic analyses. These new data are here integrated with historical and landscape evidence to examine changing patterns of fallow deer translocation and management in medieval England between the 11th and 16th century AD

Thermally induced reversible and reprogrammable actuation of tough hydrogels utilising ionoprinting and iron coordination chemistry

Ionoprinting has proven itself as a technique capable of enabling repeated post-synthesis programming of hydrogels into a variety of different shapes, achieved through a variety of different actuation pathways. To date, the technique of ionoprinting has been limited to conventional brittle hydrogels, with reversible actuation requiring a change in submersion solution. In this study, ionoprinting has been combined for the first time with a tougher interpenetrating network polymer (IPN) hydrogel with dual pH and temperature responsiveness. This new methodology eliminates the brittle material failure typically occurring during shape change programming and actuation in hydrogels, thus allowing for the realisation of more highly strained and complex shape formation than previously demonstrated. Critically, the temperature responsiveness of this system enables actuation between an unfolded (2D) and a folded (3D) shape through an external stimuli; enabling reversible actuation without a change in submersion solution. Here, the reversible thermally induced actuation is demonstrated for the first time through the formation of complex multi-folded architectures, including an origami crane bird and Miura folds, from flat hydrogel sheets. The robustness of the IPN hydrogel is demonstrated through multiple reprogramming cycles and repeated actuation of a single hydrogel sheet formed into 3D shapes (hexagon, helix and zig-zag). These advancements vastly improve the applicability of ionoprinting extending its application into areas of soft robotics, biomedical engineering and enviro intelligent sensors