Thick bone section preparation using a silicon-rubber-based sealant

A method has been developed, using a silicon-rubber-based sealant, which allows 2–3-mm-thick specimens to be maintained in a protected fluid environment for a number of months, without risk of dehydration. Following this, the specimen can be retrieved, stained, embedded and sectioned further. For example, 2-mm-thick sections of fixed unstained bone are easily examined by means of epi-illuminated polarized light and fluorescence microscopies using either conventional or confocal optics. The method could easily be extended to other tissues, for example brain tissue.     

Estimation of individual feature surface area with the vertical spatial grid

The area of an individual bounded surface (e.g. the boundary of a properly sampled cell) can be estimated from an isotropic uniform random stack of parallel sections, or of non-invasive planar scans, using the well-known spatial grid. A standing problem was to estimate the area of an individual bounded surface with an arbitrary degree of accuracy from a vertical (i.e. not isotropic) stack of sections or scans. A new tool to do this, called the ‘vertical spatial grid’, is presented.     

On asymmetric stochastic bang-bang control†

Three stochastic bang-bang control problems, the predicted miss, the linear regulator, and a complete observation model, are shown to have formally similar solutions under an asymmetric boundedness condition on the control u(t), 0<t<T.     

Verification of cell viability at progressively higher scanning forces using a hybrid atomic force and fluorescence microscope

Dry 40× and 60× microscope objectives were fitted with opaque black masks in order to eliminate reflection and scattering of light off the objective front lens assembly during oblique incidence reflection (OIR) microscopy. The reflection and scattering are shown to induce background glare that leads to degradation in the quality of the OIR images. Mask prototypes were designed and machined to snap onto the spring-loaded retractable front lens assembly of each objective. OIR images of live cells and normalized intensity line profiles are used to demonstrate that, if these alterations to the housing of the objective are implemented, background glare is significantly reduced with the 60× objective, and virtually eliminated with the 40× objective.     

Thermodynamic Assessment of the System MnO-NiO

The thermodynamic properties of pure MnO and NiO were analyzed in terms of the Debye model and a model for the magnetic transitions. The classical formula R In (β+ 1) for the magnetic entropy was found to overestimate the effect of magnetic ordering in these systems. A previous interpretation of the data for NiO was corrected. Thermodynamic functions were derived for the solid and liquid states and are given as analytic expressions. A previous assessment of the Gibbs energy of the solid solution (Mn, Ni)O from activity data was modified on statistical grounds. The results indicate that there should be a miscibility gap below 41O°C. By estimating the Gibbs energy of the liquid phase, it was possible to calculate the complete phase diagram.     

Firmness and Cell Wall Characteristics of Pasteurized Jalapeño Pepper Rings Affected by Calcium Chloride and Acetic Acid

Pepper rings packed in brine containing CaCl₂ were firmer, had higher bound calcium, chelator soluble pectin and pectin DE, and less water-soluble pectin (WSP) than peppers packed in brine containing no CaCl₂. Pepper rings packed in low acid brines (1% and 1.2% acetic acid) were firmer and had less WSP than those packed in high acid brine. Those samples (4% acetic acid) resulted in softening and pectin solubilization, but CaCl₂ resulted in less softening. Monosaccharide composition of cell walls was not affected by CaCl₂ or acetic acid. Firmness retention in CaCl₂ treated samples was probably due to greater association between calcium ions and pectic substances, which resisted acid hydrolysis.