Assembly of Hydroxy Apatite: ? Tricalcium Phosphate: Calcium Sulfate Bone Engineering Scaffolds

Directed assembly and characterization of composite Hydroxyapatite/BetaTri-CalciumPhosphate/Calcium Sulfate (HA/TCP/CaS) scaffolds with designed pore distribution for controlled solubility. Concentrated aqueous colloidal gel ink for extrusion-based direct writing was formulated with commercial HA and TCP powders blended with, ammonium poly(acrylate) (dispersant), hydroxypropylmethylcellulose (viscosifier), and Polyethyleneimine (flocculant). Prior to ink formulation, HA and TCP powders were calcined, milled, dried and characterized by X-ray diffraction. Mixtures of HA:TCP in volumetric ratios of 15:85, 35:65, and 60:40 were formulated as inks. Rice starch was formulated as ink and mixtures ceramic: rice starch blended in volumetric ratios of 85:15, 75:25, and 50:50 were produced. Disk samples (diam.11mm and 3mm thick) with an internal lattice structure of 250 micrometers rods spaced by 250 micrometers or 500 micrometers in a periodic, open pore network were printed and sintered at 1100, 1125, 1150, 1175, and 1200oC for 4 hours. The control set for each composition and pore structure had empty pores while the two test groups were filled with 2.4% Chitosan gel or Calcium Sulfate (CaS). The scaffolds were immersed in simulated body fluid and weight loss was measured by gravimetric analysis on a three day frequency. The assembled three-dimensional, binary HA/TCP structures can be sintered successfully and have both phases present in the final product. The scaffolds dissolve faster with higher TCP content and CaS filled scaffolds show dissolution behavior dominated by surface erosion of the filler phase. Micro-porosity induced by porogens does not accelerate the dissolution in vitro. In contrast, chitosan filled samples showed minimal weight loss, attributed to shielding of the TCP from SBF by the conformal and relatively stable chitosan hydrogel. Designer porous HA-TCP scaffolds may also include controlled solubility behavior by controlling HA:TCP ratio and selecting soluble pore filler. CaS may be used as a sacrificial pore filler to retard scaffold dissolution by 75 days, whereas chitosan hydrogel may persist as filler for longer periods.School of Chemical Engineerin

Sintering effects on chemical and physical properties of bioactive ceramics

The objective of this study was to characterize the chemical and physical properties of bioactive ceramics prepared from an aqueous paste containing hydroxyapatite (HA) and beta tri-calcium phosphate (β-TCP). Prior to formulating the paste, HA and β-TCP were calcined at 800 °C and 975 °C (11 h), milled, and blended into 15%/85% HA/β-TCP volume-mixed paste. Fabricated cylindrical rods were subsequently sintered to 900 °C, 1100 °C or 1250 °C. The sintered specimens were characterized by helium pycnometry, X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), and inductively coupled plasma (ICP) spectroscopy for evaluation of porosity, crystalline phase, functional-groups, and Ca:P ratio, respectively. Mechanical properties were assessed via 3-point bending and diametral compression. Qualitative microstructural evaluation using scanning electron microscopy (SEM) showed larger pores and a broader pore size distribution (PSD) for materials sintered at 900 °C and 1100 °C, whereas the 1250 °C samples showed more uniform PSD. Porosity quantification showed significantly higher porosity for materials sintered to 900 °C and 1250 °C (p< 0.05). XRD indicated substantial deviations from the 15%/85% HA/β-TCP formulation following sintering where lower amounts of HA were observed when sintering temperature was increased. Mechanical testing demonstrated significant differences between calcination temperatures and different sintering regimes (p < 0.05). Variation in chemical composition and mechanical properties of bioactive ceramics were direct consequences of calcination and sintering.Peer reviewedChemical Engineerin

ECG Simulator

If the shape of electric impulses generated by the heart are disturbed by wrong function of ECG, the physician may give an incorrect interpretation of electrocardiogram. The correct function of ECG isrealised with the help of ECG simulator. The paper presents how to make an ECG simulator from theoretic point de view and experienced in practice with good results

The Michael Reese Campus: An Interprofessional Urban Development Problem (Semester Unknown) IPRO 356

IPRO 356 is a team of students from multiple disciplines tasked with the goal of designing a second anchor for the Michael Reese to accompany the planned continued care community designed by the previous semester’s IPRO. The anchor will help meet the needs of the community as well as improve the economic condition of the current surrounding area by bringing jobs, people, and revenue to the Michael Reese site. The team will help in a revitalization of Chicago’s south side.Sponsorship: CB Richard Ellis, Jones Lang LaSalle, City of Chicago and other stakeholdersDeliverable

The Michael Reese Campus: An Interprofessional Urban Development Problem (Semester Unknown) IPRO 356: TheMichaelReeseCampusIPRO356BrochureSp11

IPRO 356 is a team of students from multiple disciplines tasked with the goal of designing a second anchor for the Michael Reese to accompany the planned continued care community designed by the previous semester’s IPRO. The anchor will help meet the needs of the community as well as improve the economic condition of the current surrounding area by bringing jobs, people, and revenue to the Michael Reese site. The team will help in a revitalization of Chicago’s south side.Sponsorship: CB Richard Ellis, Jones Lang LaSalle, City of Chicago and other stakeholdersDeliverable

The Michael Reese Campus: An Interprofessional Urban Development Problem (Semester Unknown) IPRO 356: TheMichaelReeseCampusIPRO356FinalReportSp11

IPRO 356 is a team of students from multiple disciplines tasked with the goal of designing a second anchor for the Michael Reese to accompany the planned continued care community designed by the previous semester’s IPRO. The anchor will help meet the needs of the community as well as improve the economic condition of the current surrounding area by bringing jobs, people, and revenue to the Michael Reese site. The team will help in a revitalization of Chicago’s south side.Sponsorship: CB Richard Ellis, Jones Lang LaSalle, City of Chicago and other stakeholdersDeliverable