To allow a further understanding of the pathogenesis of impaired stimulated locomotion by polymorphonuclear leukocytes (PMNs) in human neonates, we studied cellular orientation by neonatal PMNs in response to well-defined chemotactic gradients (Zigmond orientation chambers) and characterized the cytoplasmic microtubule (MT) complex of neonatal PMNs during cell orientation and movement. PMN susp...

[14C2]Coproporphyrin III, 14C-labelled in the carboxyl carbon atoms of the 2- and 4-propionate substituents, was prepared by stepwise modification of the vinyl groups of protoporphyrin IX. The corresponding porphyrinogen was used as substrate in a specific sensitive assay for coproporphyrinogen oxidase (EC 1.3.3.3) in which the rate of production of 14CO2 is measured. With this method, the Km o...

The current vs. voltage and electrical breakdown behavior for devices with micron and sub-micron gaps between conductors is studied. The limitations of the well-known but often-misinterpreted Paschen curve are discussed. The little-known modified Paschen curve, that includes field emission effects so important in understanding breakdown behavior for devices with sub-micron gaps, is described. C...

The dependence of the phagocytosis of particulate materials on their size was studied. Rabbit alveolar macrophages (AMs) obtained by lung lavage were cultured in suspensions or monolayers with Latex particles of 1 micron or 2 microns in diameter. After culturing AMs with 10(7)(-5) X 10(9) Latex particles per ml for 15 to 360 minutes, the number of phagocytized particles in each of 100 individua...

The number and proportion of neurons displaying GABA immunoreactivity were determined for 50-micron-wide columns through the thickness of 10 areas of monkey cerebral cortex, including the precentral motor area (area 4), 3 cytoarchitectonic fields of the first somatic sensory area (areas 3b, 1, and 2), 2 areas of parietal association cortex (areas 5 and 7), the first and second visual areas (are...

We developed a mouse myocardial preparation to study cellular dysfunction in acute coxsackievirus myocarditis. Thin right ventricular papillary muscles from normal mice (n = 8) were compared with muscles from mice 7 days after coxsackievirus infection (n = 7). Sarcomere shortening was studied with laser diffraction (HeNe, lambda = 623.8 nm). A servomotor was used to shorten a muscle until slack...

Three tools for the rapid prototyping of micron and sub-micron scale devices are presented. These tools represent methods for the manufacture of PEMS, or Printed micro Electro Mechanical Systems, and are enabled because they exploit the novel properties of nanocrystalline materials and their interactions with energetic beams. UV contact mask lithography was used to directly pattern metallic nan...

Abstract Accurate knowledge of the current crack length is crucial to evaluate fracture mechanical tests. At sub-micron micron scale, directly accessible via observation during in-situ experiments in electron microscopes, or indirectly calculation from sample stiffness. In work, image processing techniques were used introduce a semi-automatic technique measure lengths at scale sequences. The ut...

Abstract Micron-scale soft materials are finding a wide range of applications in bioengineering and molecular medicine, while also increasingly emerging as useful components for consumer products. The mechanical characterization such microscale objects is conventionally performed with techniques atomic force microscopy or micropipette aspiration that measure the local properties micron scale se...