In this study, spectrophotometry was used to measure changes in the absorbance properties of yeast, Grampositive, and Gram-negative bacteria after their attachment to silicon dioxide microparticles (silica). The goal of this study was to determine whether spectrophotometry is an effective method to distinguish these microorganisms from one another and determine whether they have an affinity for silicon dioxide. The experiments were performed by examining the light absorption properties of yeast, Gram-positive and Gram-negative bacteria in a spectrophotometer, both with and without silicon dioxide microparticles. The experiments produced a number of promising results. First, the spectrophotometer graphs of yeast were noticeably different from those of both Grampositive and Gram-negative bacteria. Second, the absorption of light in both Gram-positive and Gram-negative bacteria occurred at near infrared range (700-1500 nm) and, unlike yeast, the wavelengths increased when silicon dioxide microparticles were added to the suspension. When silicon dioxide microparticles were added to yeast, the absorption of light decreased during the entire wavelength interval of the spectrophotometer measurement. These results indicate that bacteria have an affinity for silicon dioxide, and that spectrophotometry may be used to distinguish yeast from bacteria and, possibly, different bacterial types from one another.

In this study, we examined if vacuum drying can be an effective way to remove water from substantia compacta, conducted in order to preserve bones for possible future transplantation. We found a number of interesting results. First, it seemed that vacuum drying removed the most of the water from substantia compacta. Second, we observed that vacuum drying did not damage the histological structure of the samples. These results indicate that vacuum drying might be used to remove water from compact bone, but more studies are required in order to assess how this method affects substantia compacta and also substantia spongiosa.

AbstractIn this study, yeast, Gram positive and Gram negative bacteria were attached to silicon dioxide microparticles or silica in order to measure their absorbance, also known as physical absorption of light, changes using spectrophotometry. The goal of the study was to determine if spectrophotometry is an effective way to distinguish microorganisms and if microorganisms have an affinity for silicon dioxide since it is a suitable material for the production of prostheses. The experiment was done by examining the light absorption properties of yeast, Gram positive and Gram negative bacteria in a spectrophotometer with and without silicon dioxide microparticles. During the experiment there have been several promising results. First of all, the spectrophotometers presented graphs of yeast were noticeably different from the graphs of both Gram positive and Gram negative bacteria. Secondly, the absorption of light in both Gram positive and Gram negative bacteria at near infrared (700-1500 nm) wavelengths increased when silicon dioxide microparticles were added to the suspension, unlike yeast. When silicon dioxide microparticles were added to yeast, the absorption of light decreased during the whole wavelength interval of the spectrophotometer measurement. The results indicate that spectrophotometry could be used to distinguish yeast from bacteria and possibly bacteria from each other. The results also suggest that silicon dioxide should not be used in the production of prostheses since it could be a favourable material for the development of biofilms.