Mechanical modeling of Intraneural Ganglion Cyst

Intraneural Ganglion Cyst is a 200 year old mystery related to nerve injury which is yet to be solved. Current treatments for the above problem are relatively simple procedures related to removal of cystic contents from the nerve. However, these treatments may result into neuropathic pain and recurrence of the cyst. The articular theory proposed by Spinner et al., (Spinner et al. 2003) takes into consideration the neurological deficit in Common Peroneal Nerve (CPN) branch of the sciatic nerve and affirms that in addition to the above treatments, ligation of articular branch results into foolproof eradication of the deficit. Mechanical Modeling of the Affected Nerve Cross Section will reinforce the articular theory (Spinner et al. 2003). As the cyst propagates, it compresses the neighboring fascicles and the nerve cross section appears like a signet ring. Hence, in order to mechanically model the affected nerve cross section; computational methods capable of modeling excessively large deformations are required. Traditional FEM produces distorted elements while modeling such deformations, resulting into inaccuracies and premature termination of the analysis. The methods described in this Master’s Thesis are effective enough to be able to simulate such deformations. The results obtained from the model adequately resemble the MRI image obtained at the same location and shows an appearance of a signet ring. This Master’s Thesis describes the neurological deficit in brief followed by detail explanation of the advanced computational methods used to simulate this problem. Finally, qualitative results show the resemblance of mechanical model to MRI images of the Nerve Cross Section at the same location validating the capability of these methods to study this neurological deficit.

Induction of Microalgal Lipids for Biodiesel Production in Tandem with Sequestration of High Carbon Dioxide Concentration

There is no doubt that sufficient energy supply is indispensable for the fulfillment of our fossil fuel crises in a stainable fashion. There have been many attempts in deriving biodiesel fuel from different bioenergy crops including corn, canola, soybean, palm, sugar cane and vegetable oil. However, there are some significant challenges, including depleting feedstock supplies, land use change impacts and food use competition, which lead to high prices and inability to completely displace fossil fuel [1-2]. In recent years, use of microalgae as an alternative biodiesel feedstock has gained renewed interest as these fuels are becoming increasingly economically viable, renewable, and carbon-neutral energy sources. One reason for this renewed interest derives from its promising growth giving it the ability to meet global transport fuel demand constraints with fewer energy supplies without compromising the global food supply. In this study, Chlorella protothecoides microalgae were cultivated under different conditions to produce high-yield biomass with high lipid content which would be converted into biodiesel fuel in tandem with the mitigation of high carbon dioxide concentration. The effects of CO2 using atmospheric and 15% CO2 concentration and light intensity of 35 and 140 µmol m-2s-1 on the microalgae growth and lipid induction were studied. The approach used was to culture microalgal Chlorella protothecoides with inoculation of 1×105 cells/ml in a 250-ml Erlenmeyer flask, irradiated with cool white fluorescent light at ambient temperature. Using these conditions we were able to determine the most suitable operating conditions for cultivating the green microalgae to produce high biomass and lipids. Nile red dye was used as a hydrophobic fluorescent probe to detect the induced intracellular lipids. Also, gas chromatograph mass spectroscopy was used to determine the CO2 concentrations in each culture flask using the closed continuous loop system. The goal was to study how the 15% CO2 concentration was being used up by the microalgae during cultivation. The results show that the condition of high light intensity of 140 µmol m-2s-1 with 15% CO2 concentration obtain high cell concentration of 7 x 105 cells mL-1 after culturing Chlorella protothecoides for 9 to 10 day in both open and closed systems respectively. Higher lipid content was estimated as indicated by fluorescence intensity with 1.3 to 2.5 times CO2 reduction emitted by power plants. The particle size of Chlorella protothecoides increased as well due to induction of lipid accumulation by the cells when culture under these condition (140 µmol m-2s-1 with 15% CO2 concentration).

SIMULATING LARGE DEFORMATION OF INTRANEURAL GANGLION CYST USING FINITE ELEMENT METHOD

Intraneural Ganglion Cyst is disorder observed in the nerve injury, it is still unknown and very difficult to predict its propagation in the human body so many times it is referred as an unsolved history. The treatments for this disorder are to remove the cystic substance from the nerve by a surgery. However these treatments may result in neuropathic pain and recurrence of the cyst. The articular theory proposed by Spinner et al., (Spinner et al. 2003) considers the neurological deficit in Common Peroneal Nerve (CPN) branch of the sciatic nerve and adds that in addition to the treatment, ligation of articular branch results into foolproof eradication of the deficit. Mechanical modeling of the affected nerve cross section will reinforce the articular theory (Spinner et al. 2003). As the cyst propagates, it compresses the neighboring fascicles and the nerve cross section appears like a signet ring. Hence, in order to mechanically model the affected nerve cross section; computational methods capable of modeling excessively large deformations are required. Traditional FEM produces distorted elements while modeling such deformations, resulting into inaccuracies and premature termination of the analysis. The methods described in research report have the capability to simulate large deformation. The results obtained from this research shows significant deformation as compared to the deformation observed in the conventional finite element models. The report elaborates the neurological deficit followed by detail explanation of the Smoothed Particle Hydrodynamic approach. Finally, the results show the large deformation in stages and also the successful implementation of the SPH method for the large deformation of the biological organ like the Intra-neural ganglion cyst.

Production of Recombinant Trichoderma Reesei Endoglucanase Protein CEL7B by Using Kluyveromyces Lactis

This research is about producing recombinant Trichoderma reesei endoglucanase Cel7B by using Kluyveromyces lactis, transformed with chromosomally integrated Cel7B cDNA, as a host cell (K. lactis Cel7B). Cel7B is one of the glycoside hydrolyze family of proteins that are produced by T. reesei. Cel7B together with other endoglucanases, exoglucanases, and â-glucosidases hydrolyze cellulose to glucose, which can then be fermented to biofuels or other value-added products. The research objective of this MS project is to examine favorable fermentation conditions for recombinant Cel7B enzyme production and improved activity. Production of enzyme on different types of media was examined, and the activity of the enzyme was measured by using different tools or procedures. The first condition tested for was using different concentrations of galactose as a carbon and energy source; however galactose also acts as a potent promoter of recombinant Cel7B expression in K. lactis Cel7B. The purpose of this method is to determine the relationship between production of enzyme with increasing sugar concentration. The second culture condition test was using different types of media: a complex medium-yeast extract, peptone, galactose (YPGal); a minimal medium-yeast nitrogen base (YNB) with galactose; and a minimal medium with supplement-yeast nitrogen base with casamino acid (YBC), a nitrogen source, with galactose. The third condition was using different types of reactors or fermenters: a small reactor (shake flask) and a larger automated bioreactor (BioFlo 3000 fermenter). The purpose of this method is to determine the quantity of the protein produced by using different environments of production. Different tools to determine the presence and activity of Cel7B enzyme were used. For the presence of enzyme, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used. Secondly, to detect enzyme activity, the carboxymethyl cellulose- 3,5-dinitrosalicylic acid (CMC- DNS) assay was employed. SDS-PAGE showed that the enzyme band was at 67 kDa, which is larger than native Cel7B (52 kDa.), likely due to over glycolylation during post-translational processing in K. lactis. For the different types of media used in our fermentation, recombinant Cel7B was produced from yeast extract peptone galactose (YPGal), and yeast nitrogen base with casamino acid (YBC), but was not produced and no activity was detected from yeast nitrogen base (YNB). This experiment concluded that the Cel7B production requires the amino acid resources as part of fermentation medium. In experiments where recombinant Cel7B net activity was measured at 1% galactose initial concentration in YPGal and YBC media, higher enzyme activity was detected for the complex medium YPGal. Higher activity of recombinant Cel7B was detected for flask culture in 2% galactose compared to 1% galactose for YBC medium. Two bioreactor experiments were conducted under these culture conditions at 30°C, pH 7.0, dissolved oxygen of 50% of saturation, and 250 rpm agitation (variable depending on DO control) K. lactis-Cel7B yeast growth curves were quite reproducible with maximum optical density (O.D) at 600 nm of between 7 and 8 (when factoring dilution of 10:1). Galactose was consumed rapidly during the first 15 hours of bioreactor culture and recombinant Cel7B started to appear in the culture at 10-15 hours and increased thereafter up to a maximum of between 0.9 and 1.6 mg/mL/hr in these experiments. These bioreactor enzyme activity results are much higher than comparable experiments conducted with flask-scale culture (0.5 mg/mL/hr). In order to achieve the highest recombinant Cel7B activity from batch culture of K. lactis-Cel7B, based on this research it is best to use a complex medium, 2% initial galactose concentration, and an automated bioreactor where good control of temperature, pH, and dissolved oxygen can be achieved.