Alternative Reaction Pathways to Metformin Hydrochloride

Metformin Hydrochloride is an important pharmaceutical used for the treatment of type 2 diabetes. The current manufacturing of this product involves a well-known and proven process. The process includes the dissolution and reaction, followed by the precipitation of Metformin Hydrochloride. Although reliable and effective, the current process relies on the use of a solvent; which later needs to be eliminated from the precipitates. The purpose of this project is the investigation of an alternative reaction pathway which will avoid the use of solvents and simplify the final purification stage. The anticipated benefits include reduced costs for the processing and a final product which is closer to meet FDA and quality standards. These steps will eventually result in reducing the final market value of this important pharmaceutical. Preliminary experiments were conducted using micro and laboratory scale solvent-less reacting environments. These experiments allowed identifying the presence of a single chemical reaction. The characterization results suggest that the alternative pathway can successfully synthesize Metformin Hydrochloride. Further characterization and testing protocols are currently being formulated.https://engagedscholarship.csuohio.edu/u_poster_2014/1035/thumbnail.jp

Oxygen Diffusion Through Natural Extracellular Matrices: Implications for Estimating Critical Thickness Values in Tendon Tissue Engineering

Oxygen is necessary for maintaining cell proliferation and viability and extracellular matrix (ECM) production in 3-dimensional tissue engineering. Typically, diffusion is the primary mode for oxygen transport in vitro; thus, ensuring an adequate oxygen supply is essential. In this study, we determined the oxygen diffusion coefficients of 3 natural ECMs that are being investigated as construct scaffolds for tendon tissue engineering: small-intestine submucosa (SIS), human dermis (Alloderm (R)), and canine fascia lata. Diffusion coefficients were determined using a standard diffusion cell system. The ranges for each matrix type were: SIS: 7 x 10(-6) - 2 x 10(-5) cm(2)/s, Alloderm (R): 1.9 - 3.1 x 10(-5) cm(2)/s, and canine fascia lata: 1.6 - 4 x 10(-5) cm(2)/s. We used the experimental oxygen diffusivity data for these natural ECMs in a mathematical model of oxygen diffusion through a cell-seeded scaffold to estimate the critical size of cell-seeded scaffold that can be cultured in vitro

Reaction Engineering Routes to Waste Gasification for Sustainable Living Environments

There is an increasing pressure to reduce waste generation and dependence upon fossil fuels in our society. The approach investigated in this project aims to address both concerns by formulating a low-temperature gasification process to process long-chain polymers typically found in municipal waste. Gasification routes which convert plastic and bio-waste into useful fuel syngas products has been extensively investigated. The novelty of the approach examined here consists on the use of a variety of catalysts, which can promote high conversion in gasification reactions at much lower temperature and pressure conditions. This route overcomes some of the financial and environmental shortcomings of typical gasification routes, such as incineration, currently in use as waste-management strategies. Utilizing a small batch reactor, the kinetics of several, predominantly polyethylene, waste simulants have been examined in the presence of both platinum and ruthenium-based catalysts. Using gas chromatography, the conversion of the carbon source was quantified and compared for the two different catalysts and different reaction conditions. Promising results were obtained, these results compare favorably with results found in the literature. A phenomenological model has been formulated to characterize the liquid phase gasification reactions and their interrelation with transport phenomena occurring in an heterogeneous reaction environment. Through the use of computational fluid dynamics (CFD), the effect of mixer speed on vortex shape has been modeled. These results are currently being incorporated into the model in the form of a detailed characterization of transport phenomena occurring during the gasification dynamics. Moreover, the refined model is anticipated to enable optimization of the reactor operation, and reducing or de-convoluting any transport limitation that may be affecting kinetic determinations.https://engagedscholarship.csuohio.edu/u_poster_2014/1030/thumbnail.jp

An Analytical Model for Rotator Cuff Repairs

Background Currently, natural and synthetic scaffolds are being explored as augmentation devices for rotator cuff repair. When used in this manner, these devices are believed to offer some degree of load sharing; however, no studies have quantified this effect. Furthermore, the manner in which loads on an augmented rotator cuff repair are distributed among the various components of the repair is not known, nor is the relative biomechanical importance of each component. The objectives of this study are to (1) develop quasi-static analytical models of simplified rotator cuff repairs, (2) validate the models, and (3) predict the degree of load sharing provided by an augmentation scaffold. Methods The individual components of the repair constructs were modeled as non-linear springs, and the model equations were formulated based on the physics of springs in series and parallel. The model was validated and used to predict the degree of load sharing provided by a scaffold. Parametric sensitivity analysis was used to identify which of the component(s)/parameter(s) most influenced the mechanical behavior of the augmented repair models. Findings The validated models predict that load will be distributed ∼ 70–80% to the tendon repair and ∼ 20–30% to the augmentation component. The sensitivity analysis suggests that the greatest improvements in the force carrying capacity of a tendon repair may be achieved by improving the properties of the bone–suture–tendon interface. Future studies will perform parametric simulation to illustrate the manner in which changes to the individual components of the repair, representing different surgical techniques and scaffold devices, may influence the biomechanics of the repair construct

An Analytical Model for Rotator Cuff Repairs

Background Currently, natural and synthetic scaffolds are being explored as augmentation devices for rotator cuff repair. When used in this manner, these devices are believed to offer some degree of load sharing; however, no studies have quantified this effect. Furthermore, the manner in which loads on an augmented rotator cuff repair are distributed among the various components of the repair is not known, nor is the relative biomechanical importance of each component. The objectives of this study are to (1) develop quasi-static analytical models of simplified rotator cuff repairs, (2) validate the models, and (3) predict the degree of load sharing provided by an augmentation scaffold. Methods The individual components of the repair constructs were modeled as non-linear springs, and the model equations were formulated based on the physics of springs in series and parallel. The model was validated and used to predict the degree of load sharing provided by a scaffold. Parametric sensitivity analysis was used to identify which of the component(s)/parameter(s) most influenced the mechanical behavior of the augmented repair models. Findings The validated models predict that load will be distributed ∼ 70–80% to the tendon repair and ∼ 20–30% to the augmentation component. The sensitivity analysis suggests that the greatest improvements in the force carrying capacity of a tendon repair may be achieved by improving the properties of the bone–suture–tendon interface. Future studies will perform parametric simulation to illustrate the manner in which changes to the individual components of the repair, representing different surgical techniques and scaffold devices, may influence the biomechanics of the repair construct

Simple Model of Capillary Condensation in porous media

We employ a simple model to describe the phase behavior of 4He and Ar in a hypothetical porous material consisting of a regular array of infinitely long, solid, parallel cylinders. We find that high porosity geometries exhibit two transitions: from vapor to film and from film to capillary condensed liquid. At low porosity, the film is replaced by a ``necking'' configuration, and for a range of intermediate porosity there are three transitions: from vapor to film, from film to necking and from necking to a capillary condensed phase.Comment: 14 pages, 7 figure

Analysis and characterization of neutron scattering of a Linear Accelerator (LINAC) on medical applications.

In several theoretical and experimental studies, the topic of the undesirable generation of photoneutrons in rooms where a linear accelerator (LINAC) operates has been discussed. When energies above 10 MeV are used to produce X-rays and give radiotherapy treatment to patients resulting in additional radiation to patients. Accordingly, an analysis and characterization of the neutron scattering distribution on different zones in a treatment room contributes to evaluate the radiological health risk to patients, technical and other workers involved in treatment. For the evaluation, a device developed at the PAD-IFUNAM formed by a CR-39 detector enclosed by two 3mm thick acrylic plates was employed. To avoid environmental contamination, the CR-39 and the acrylics plates are enclosed in a round plastic box. Sixteen of these devices were settled in different places inside the treatment room, where a linear accelerator is used. The results show a significant concentration of neutron scattering in areas near the head of irradiation. The recommendation will be to evaluate the neutron scattering concentration in all rooms that’s operates a LINAC in order to verify the radiological health risk and to mitigate the neutron scattering when concentration levels are to high like those in our case, in order to avoid unnecessary exposition to patients and personnel in general

The Biomechanical Role of Scaffolds in Augmented Rotator Cuff Tendon Repairs

Background Scaffolds continue to be developed and used for rotator cuff repair augmentation; however, the appropriate scaffold material properties and/or surgical application techniques for achieving optimal biomechanical performance remains unknown. The objectives of the study were to simulate a previously validated spring-network model for clinically relevant scenarios to predict: (1) the manner in which changes to components of the repair influence the biomechanical performance of the repair and (2) the percent load carried by the scaffold augmentation component. Materials and methods The models were parametrically varied to simulate clinically relevant scenarios, namely, changes in tendon quality, altered surgical technique(s), and different scaffold designs. The biomechanical performance of the repair constructs and the percent load carried by the scaffold component were evaluated for each of the simulated scenarios. Results The model predicts that the biomechanical performance of a rotator cuff repair can be modestly increased by augmenting the repair with a scaffold that has tendon-like properties. However, engineering a scaffold with supraphysiologic stiffness may not translate into yet stiffer or stronger repairs. Importantly, the mechanical properties of a repair construct appear to be most influenced by the properties of the tendon-to-bone repair. The model suggests that in the clinical setting of a weak tendon-to-bone repair, scaffold augmentation may significantly off-load the repair and largely mitigate the poor construct properties. Conclusions The model suggests that future efforts in the field of rotator cuff repair augmentation may be directed toward strategies that strengthen the tendon-to-bone repair and/or toward engineering scaffolds with tendon-like mechanical properties

Near-infrared thermal emissivity from ground based atmospheric dust measurements at ORM

We present an analysis of the atmospheric content of aerosols measured at Observatorio del Roque de los Muchachos (ORM; Canary Islands). Using a laser diode particle counter located at the Telescopio Nazionale Galileo (TNG) we have detected particles of 0.3, 0.5, 1.0, 3.0, 5.0 and 10.0 um size. The seasonal behavior of the dust content in the atmosphere is calculated. The Spring has been found to be dustier than the Summer, but dusty conditions may also occur in Winter. A method to estimate the contribution of the aerosols emissivity to the sky brightness in the near-infrared (NIR) is presented. The contribution of dust emission to the sky background in the NIR has been found to be negligible comparable to the airglow, with a maximum contribution of about 8-10% in the Ks band in the dusty days.Comment: 6 pages, 3 figures, 6 tables, accepted for publication in MNRA

Dynamic Analysis of Unidirectional Pressure Infiltration of Porous Preforms by Pure Metals

Unidirectional pressure infiltration of porous preforms by molten metals is investigated numerically. A phenomenological model to describe fluid flow and transport phenomena during infiltration of fibrous preforms by a metal is formulated. The model describes the dynamics of the infiltration process, the temperature distribution, and solid fraction distribution. The numerical results are compared against classical asymptotic analyses and experimental results. This comparison shows that end effects may become important and render asymptotic results unreliable for realistic samples. Fiber volume fraction and initial temperature appear as the factors most strongly influencing infiltration. Metal superheating affects not only the length of the two-phase zone but also the solid fraction distribution in the two-phase zone. The effect of constant applied pressure, although significant on the infiltration velocity, is almost negligible on the two-phase zone length and on solid fraction distribution. When the initial preform temperature is below the metal melting point, and constant pressure is applied under adiabatic conditions, the flow ceases when sufficient solidification occurs to obstruct it. A comparison with literature experiments proves the model to be an efficient predictive tool in the analysis of infiltration processes for different preform/melt systems