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Articles 1 - 11 of 11
Full-Text Articles in Biomedical Engineering and Bioengineering
Procedure To Quantify Biofilm Activity In Carriers Used In Wastewater Treatment Systems, James Bolton, Archana Tummala, Chirag Kapadia, Manoj Dandamudi, Joanne M. Belovich
Procedure To Quantify Biofilm Activity In Carriers Used In Wastewater Treatment Systems, James Bolton, Archana Tummala, Chirag Kapadia, Manoj Dandamudi, Joanne M. Belovich
Chemical & Biomedical Engineering Faculty Publications
A procedure is presented for evaluating and comparing the biological activity of biofilms attached to various biofilm carriers by measurement of the glucose consumption rate. This technique allows for the economical design and selection of small particulate biofilm carriers that will maximize substrate removal when used in industrial-scale fluidized bioreactors. Methods for ensuring reproducible results are described. To support the glucose consumption rate findings, biofilm dry weights were obtained at the conclusion of activity rate experiments, and scanning electron micrographs were taken to evaluate the presence of biofilm and to view surface characteristics. Fourteen different biofilm carriers were evaluated ranging …
The Influence Of Ultrasonic Setting On Fluoride Release From Glass Polyalkenoate Cements, N. Rushe, Mark R. Towler
The Influence Of Ultrasonic Setting On Fluoride Release From Glass Polyalkenoate Cements, N. Rushe, Mark R. Towler
Chemical and Biochemical Engineering Faculty Research & Creative Works
The effects of ultrasonic setting on fluoride release from glass polyalkenoate cements (GPC) were investigated. Cements based on two different aluminosilicate glasses that contained silica, alumina, phosphate, and strontia were used for the experiment. A series of GPCs were examined to show that increased release F- ion occurs, regardless of GPC composition. The results show that there is a greater release of fluoride from the ultrasonically set samples than those set chemically, regardless of the chemical composition. The snap set caused by the ultrasound is likely to be due to a combination of cavitation, improved mixing of the constituents, …
Influence Of Two Changes In The Composition Of An Acrylic Bone Cement On Some Of Its Properties: The Case Of Surgical Simplex® P, S. Madigan, Mark R. Towler, G. Lewis
Influence Of Two Changes In The Composition Of An Acrylic Bone Cement On Some Of Its Properties: The Case Of Surgical Simplex® P, S. Madigan, Mark R. Towler, G. Lewis
Chemical and Biochemical Engineering Faculty Research & Creative Works
Influence of two changes in the composition of a self-curing acrylic bone cement on some of its properties are discussed. Acrylic bone cements are widely used in orthopedic surgery for the fixation of joint prosthesis and in vertebroplasty and kyphoplasty for the stabilization and augmentation of fractured vertebrae. The cement's curing process is the result of a free-radical polymerization of a mixture of poly (methyl 1 methacrylate) [PMMA] containing powder and a liquid monomer that has methyl methacrylate (MMA) in it. It is initiated by the decomposition of benzoyl peroxide (BPO) in the powder, activated by a tertiary amine in …
Calcium And Zinc Ion Release From Polyalkenoate Cements Formed From Zinc Oxide/Apatite Mixtures, Mark R. Towler, S. Kenny, D. Boyd, T. Pembroke, M. Buggy, A. Guida, R. G. Hill
Calcium And Zinc Ion Release From Polyalkenoate Cements Formed From Zinc Oxide/Apatite Mixtures, Mark R. Towler, S. Kenny, D. Boyd, T. Pembroke, M. Buggy, A. Guida, R. G. Hill
Chemical and Biochemical Engineering Faculty Research & Creative Works
Calcium and zinc ion release from hydroxyapatite-zinc oxide-poly (acrylic acid) (HAZnO-PAA) composite cements into deionised water was investigated as a function of HA content, PAA concentration, PAA molecular weight and maturation time. At any given maturation time, zinc ion release was constant until the HA content was at the maximum loading (60 wt%) resulting in the cement matrix breaking up, allowing exacerbated ion release. The calcium ion release increased with increased HA content in the composite until the maximum loading where the release drops off. Up to this point, the release of both ionic species was proportional to square root …
The Antibacterial Effects Of Zinc Ion Migration From Zinc-Based Glass Polyalkenoate Cements, D. Boyd, H. Li, D. A. Tanner, Mark R. Towler, J. G. Wall
The Antibacterial Effects Of Zinc Ion Migration From Zinc-Based Glass Polyalkenoate Cements, D. Boyd, H. Li, D. A. Tanner, Mark R. Towler, J. G. Wall
Chemical and Biochemical Engineering Faculty Research & Creative Works
Zinc-based glass polyalkenoate cements have been synthesised and their potential use in orthopaedic applications investigated. Zinc ions were released from the materials in a rapid burst over the first 24 h after synthesis, with the release rate falling below detectable levels after 7 days. Cement-implanted bone samples were prepared, and the released zinc was shown, using energy dispersive X-ray analysis, to penetrate from the cement into the adjacent bone by up to 40 μm. Finally, the cements exhibited antibacterial activity against Streptococcus mutans and Actinomyces viscosus that reflected the pattern of zinc release, with the inhibition of growth greatest shortly …
Desulfovibrio Desulfuricans G20 Tetraheme Cytochrome Structure At 1.5 A˚ And Cytochrome Interaction With Metal Complexes, Mrunalini Pattarkine, J J. Tanner, C A. Bottoms, Y H. Lee, Judy D. Wall
Desulfovibrio Desulfuricans G20 Tetraheme Cytochrome Structure At 1.5 A˚ And Cytochrome Interaction With Metal Complexes, Mrunalini Pattarkine, J J. Tanner, C A. Bottoms, Y H. Lee, Judy D. Wall
Faculty Works
The structure of the type I tetraheme cytochrome c3 from Desulfovibrio desulfuricans G20 was determined to 1.5 A˚ by X-ray crystallography. In addition to the oxidized form, the structure of the molybdate-bound form of the protein was determined from oxidized crystals soaked in sodium molybdate. Only small structural shifts were obtained with metal binding, consistent with the remarkable structural stability of this protein. In vitro experiments with pure cytochrome showed that molybdate could oxidize the reduced cytochrome, although not as rapidly as U(VI) present as uranyl acetate. Alterations in the overall conformation and thermostability of the metal-oxidized protein were investigated …
An Investigation Into The Structure And Reactivity Of Calcium-Zinc-Silicate Ionomer Glasses Using Mas-Nmr Spectroscopy, D. Boyd, Mark R. Towler, R. V. Law, R. G. Hill
An Investigation Into The Structure And Reactivity Of Calcium-Zinc-Silicate Ionomer Glasses Using Mas-Nmr Spectroscopy, D. Boyd, Mark R. Towler, R. V. Law, R. G. Hill
Chemical and Biochemical Engineering Faculty Research & Creative Works
The suitability of Glass Polyalkenoate Cements (GPCs) for orthopaedic applications is retarded by the presence in the glass phase of aluminum, a neurotoxin. Unfortunately, the aluminum ion plays an integral role in the setting process of GPCs and its absence is likely to hinder cement formation. However, the authors have previously shown that aluminum-free GPCs may be formulated based on calcium zinc silicate glasses and these novel materials exhibit significant potential as hard tissue biomaterials. However, there is no data available on the structure of these glasses. 29Si MAS-NMR, differential thermal analysis (DTA), X-ray diffraction (XRD), and network crosslink density …
Ultrasonically Set Glass Polyalkenoate Cements For Orthodontic Applications, D. A. Tanner, N. Rushe, Mark R. Towler
Ultrasonically Set Glass Polyalkenoate Cements For Orthodontic Applications, D. A. Tanner, N. Rushe, Mark R. Towler
Chemical and Biochemical Engineering Faculty Research & Creative Works
There is an accepted clinical requirement for a luting cement that can be command set upon satisfactory placement of an orthodontic appliance onto dentition. This work evaluates the suitability of ultrasound, imparted from a dental scaler, as a potential mechanism for achieving this. The net setting times and subsequent compressive strengths of a range of commercial and experimental glass polyalkenoate cements (GPCs) were evaluated, using modified ISO 9917 methods, when set both chemically and by ultrasound. The ultrasound was applied to the GPC through an orthodontic brace. It was possible to command set GPCs by the application of five to …
Optimisation Of The Composition Of An Acrylic Bone Cement: Application To Relative Amounts Of The Initiator And The Activator/Co-Initiator In Surgical Simplex®P, S. Madigan, M. R. Towler, G. Lewis
Optimisation Of The Composition Of An Acrylic Bone Cement: Application To Relative Amounts Of The Initiator And The Activator/Co-Initiator In Surgical Simplex®P, S. Madigan, M. R. Towler, G. Lewis
Chemical and Biochemical Engineering Faculty Research & Creative Works
In cemented arthroplasties, the two-part self-curing acrylic bone cement is currently the only material used for anchoring the total joint replacement to the contiguous bone. In virtually all commercially available formulations of this cement, the agents used for the initiation and activation/co-initiation of the radical polymerisation reaction are benzoyl peroxide (BPO) and N, N dimethyl-paratoluidine (DMPT), respectively. There are no reports in the open literature on the rationale for the amounts of these and other constituents in the formulations of the cement. Given the concerns that have been raised in the literature regarding the effect of residual DMPT on the …
Quantitative Measurement Of The Brã¶Nsted Acid Sites In Solid Acids: Toward A Single-Site Design Of Mo-Modified Zsm-5 Zeolite, Jean-Philippe Tessonnier, Benoit Louis, Stephane Walspurger, Jean Sommer, Marc-Jacques Ledoux, Cuong Pham-Huu
Quantitative Measurement Of The Brã¶Nsted Acid Sites In Solid Acids: Toward A Single-Site Design Of Mo-Modified Zsm-5 Zeolite, Jean-Philippe Tessonnier, Benoit Louis, Stephane Walspurger, Jean Sommer, Marc-Jacques Ledoux, Cuong Pham-Huu
Jean-Philippe Tessonnier
On the basis of our previous H/D exchange studies devoted to the quantification of the number of Bro¨nsted acid sites in solid acids, we report here an innovative approach to determine both the amount and the localization of Mo atoms inside the Mo/ZSM-5 catalyst, commonly used for the methane dehydroaromatization reaction. The influence of Mo introduction in the MFI framework was studied by means of BET, X-ray diffraction, 27Al magic angle spinning NMR, NH3 temperature-programmed desorption, and H/D isotopic exchange techniques. A dependence was found between the decrease of acidic OH groups and the Mo content. Depending on the Si/Al …
Intracellular Signaling Networks In The Immune Response: Pathways Activated By Interleukin-2 And-4 Receptors And Their Roles In T Cell Proliferation, Kristen K. Comfort
Intracellular Signaling Networks In The Immune Response: Pathways Activated By Interleukin-2 And-4 Receptors And Their Roles In T Cell Proliferation, Kristen K. Comfort
Chemical and Materials Engineering Faculty Publications
Cells sense and respond to chemical and physical stimuli through signal transduction pathways, which mediate cell proliferation, differentiation, migration, and survival. The cytokines interleukin-2 (IL-2) and interleukin-4 (IL-4) are key regulators of the adaptive immune system, particularly influencing the clonal expansion and differentiation of T cells. At least in culture, both synergistic and antagonistic effects of IL-2 and -4 co-stimulation have been reported; the antagonism, when observed, is thought to arise from the utilization of a common subunit shared by IL-2 and IL-4 receptors. We have sought to characterize IL-2 and IL-4 signaling at the level of intracellular pathways activated …