Computational fluid dynamic analysis of bioprinted self-supporting perfused tissue models

Natural tissues are incorporated with vasculature, which is further integrated with a cardiovascular system responsible for driving perfusion of nutrient‐rich oxygenated blood through the vasculature to support cell metabolism within most cell‐dense tissues. Since scaffold‐free biofabricated tissues being developed into clinical implants, research models, and pharmaceutical testing platforms should similarly exhibit perfused tissue‐like structures, we generated a generalizable biofabrication method resulting in self‐supporting perfused (SSuPer) tissue constructs incorporated with perfusible microchannels and integrated with the modular FABRICA perfusion bioreactor. As proof of concept, we perfused an MLO‐A5 osteoblast‐based SSuPer tissue in the FABRICA. Although our resulting SSuPer tissue replicated vascularization and perfusion observed in situ, supported its own weight, and stained positively for mineral using Von Kossa staining, our in vitro results indicated that computational fluid dynamics (CFD) should be used to drive future construct design and flow application before further tissue biofabrication and perfusion. We built a CFD model of the SSuPer tissue integrated in the FABRICA and analyzed flow characteristics (net force, pressure distribution, shear stress, and oxygen distribution) through five SSuPer tissue microchannel patterns in two flow directions and at increasing flow rates. Important flow parameters include flow direction, fully developed flow, and tissue microchannel diameters matched and aligned with bioreactor flow channels. We observed that the SSuPer tissue platform is capable of providing direct perfusion to tissue constructs and proper culture conditions (oxygenation, with controllable shear and flow rates), indicating that our approach can be used to biofabricate tissue representing primary tissues and that we can model the system in silico

Qualitative extension of the EC′ Zone Diagram to a molecular catalyst for a multi-electron, multi-substrate electrochemical reaction

Traverse the EC′ Zone Diagram with a molecular H 2 -evolving electrocatalyst through systematic variation of the acid p K a , scan rate, acid concentration and catalyst concentration

Physioxia promotes the articular chondrocyte-like phenotype in human chondroprogenitor-derived self-organized tissue

Introduction: Biomaterial-based tissue engineering has not successfully reproduced the structural architecture or functional mechanical properties of native articular cartilage. In scaffold-free tissue engineering systems, cells secrete and organize the entire extracellular matrix over time in response to environmental signals such as oxygen level. In this study, we investigated the effect of oxygen on the formation of neocartilage from human-derived chondrogenic cells. Materials and Methods: Articular chondrocytes (ACs) and articular cartilage progenitor cells (ACPs) derived from healthy human adults were guided toward cell condensation by centrifugation onto plate inserts that were uncoated or coated with either agarose or fibronectin. Neocartilage discs were cultured at hyperoxic (20%) or physioxic (5%) oxygen levels, and biochemical, biomechanical, and molecular analyses were used to compare the cartilage produced by ACs versus ACPs. Results: Fibronectin-coated inserts proved optimal for growing cartilaginous discs from both cell types. In comparison with culture in hyperoxia, AC neocartilage cultured at physioxia exhibited a significant increase in chondrogenic gene expression, proteoglycan production, and mechanical properties with a concomitant decrease in collagen content. At both oxygen levels, ACP-derived neocartilage produced tissue with significantly enhanced mechanical properties and collagen content relative to AC-derived neocartilage. Both ACs and ACPs produced substantial collagen II and reduced levels of collagens I and X in physioxia relative to hyperoxia. Neocartilage from ACPs exhibited anisotropic organization characteristic of native cartilage with respect to collagen VI of the pericellular matrix when compared with AC-derived neocartilage; however, only ACs produced abundant surface-localized lubricin. Discussion and Conclusions: Guiding human-derived cells toward condensation and subsequent culture in physioxia promoted the articular cartilage tissue phenotype for ACs and ACPs. Unlike ACs, ACPs are clonable and highly expandable while retaining chondrogenicity. The ability to generate large tissues utilizing a scaffold-free approach from a single autologous progenitor cell may represent a promising source of neocartilage destined for cartilage repair

Chlamydophila (Chlamydia) pneumoniae promotes Ab 1-42 amyloid processing in Neuronal Cells: A Pathogenic Trigger for Alzheimer\u27s Disease

Background: Previously, our laboratory identified Chlamydophila (Chlamydia) pneumoniae (Cpn) in autopsied sporadic AD brains. Furthermore, we have developed a BALB/c mouse model that demonstrated infection-induced amyloid plaques similar to those found in AD, and demonstrated that Cpn infection of neuronal cells inhibited apoptotic pathways of cell death. Hypothesis: Our current studies address whether infection with Cpn in neuronal cells triggers abnormal cleavage of the beta amyloid precursor protein (bAPP) into Ab1-42, thereby contributing to amyloid plaque formation characteristic of the pathology identified in AD. Materials and Methods: Human neuroblastoma cells were infected with the respiratory strain AR39 Cpn in vitro, then amyloid processing was analyzed and quantitated using immunocytochemistry, Western blotting and ELISA assays. Results: Cpn was shown to infect neuronal cells and induce intracellular amyloid processing. Cpn infection yielded cytoplasmic labeling of Ab 1-42 that was increased relative to uninfected cells. The ELISA assay revealed that in neuronal cell lysates, Ab 1-42 in the infected cells was increased 3 to 16-fold over the uninfected cells, from 24 to 72hr post infection. Western blot analysis confirmed an increase in Ab 1-42 in the infected neuronal cell lysates. Conclusions: These data suggest that infection of neuronal cells with Chlamydophila (Chlamydia) pneumoniae alters the processing of bAPP, thereby producing Ab1-42. Therefore, these studies and previous research reported by our laboratory support the implication of Cpn as a pathogenic agent in perpetuating the hallmark amyloid plaque formations observed in AD. This concept holds major therapeutic considerations for future studies.https://digitalcommons.pcom.edu/posters/1004/thumbnail.jp

Distribution and dynamics of nitrogen and microbial plankton in southern Lake Michigan during spring transition 1999–2000

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95655/1/jgrc9187.pd

A parsimonious explanation for intersecting perinatal mortality curves: understanding the effects of race and of maternal smoking

BACKGROUND: Neonatal mortality rates among black infants are lower than neonatal mortality rates among white infants at birth weights <3000 g, whereas white infants have a survival advantage at higher birth weights. This finding is also observed when birth weight-specific neonatal mortality rates are compared between infants of smokers and non-smokers. We provide a parsimonious explanation for this paradoxical phenomenon. METHODS: We used data on births in the United States in 1997 after excluding those with a birth weight <500 g or a gestational age <22 weeks. Birth weight- and gestational age-specific perinatal mortality rates were calculated per convention (using total live births at each birth weight/gestational age as the denominator) and also using the fetuses at risk of death at each gestational age. RESULTS: Perinatal mortality rates (calculated per convention) were lower among blacks than whites at lower birth weights and at preterm gestational ages, while blacks had higher mortality rates at higher birth weights and later gestational ages. With the fetuses-at-risk approach, mortality curves did not intersect; blacks had higher mortality rates at all gestational ages. Increases in birth rates and (especially) growth-restriction rates presaged gestational age-dependent increases in perinatal mortality. Similar findings were obtained in comparisons of smokers versus nonsmokers. CONCLUSIONS: Formulating perinatal risk based on the fetuses-at-risk approach solves the intersecting perinatal mortality curves paradox; blacks have higher perinatal mortality rates than whites and smokers have higher perinatal mortality rates than nonsmokers at all gestational ages and birth weights

Discovery of Three Distant, Cold Brown Dwarfs in the WFC3 Infrared Spectroscopic Parallels Survey

We present the discovery of three late type (>T4) brown dwarfs, including a probable Y dwarf, in the WFC3 Infrared Spectroscopic Parallels (WISP) Survey. We use the G141 grism spectra to determine the spectral types of the dwarfs and derive distance estimates based on a comparison with nearby T dwarfs with known parallaxes. These are the most distant spectroscopically confirmed T/Y dwarfs, with the farthest at an estimated distance of ~400 pc. We compare the number of cold dwarfs found in the WISP survey with simulations of the brown dwarf mass function. The number found is generally consistent with an initial stellar mass function dN/dM \propto M^{-\alpha} with \alpha = 0.0--0.5, although the identification of a Y dwarf is somewhat surprising and may be indicative of either a flatter absolute magnitude/spectral type relation than previously reported or an upturn in the number of very late type brown dwarfs in the observed volume.Comment: Accepted for publication by ApJ Letters. 10 pages, 2 figure

The Ursinus Weekly, November 14, 1974

15 U.C. seniors named to Who\u27s who • Puzzle solved • Letter to the Editor • Part two: The Legend of the three doors • Growth of the Greeks: Green and gold - KDK • Library metamorphosis • Rebuilding Bears lose to Dickinson • Only one game lost • Alumna corner: First foreign student • Pages from Ursinus past: Freshmen regulations • Photo reviewhttps://digitalcommons.ursinus.edu/weekly/1025/thumbnail.jp

Mental Health Service Utilization before and after Receipt of a Service‐Connected Disability Award for PTSD: Findings from a National Sample

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146624/1/hesr12859.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146624/2/hesr12859-sup-0001-AppendixSA1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146624/3/hesr12859_am.pd