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Institution

Saint Francis University

EducationLoretto, Pennsylvania, United States
About: Saint Francis University is a education organization based out in Loretto, Pennsylvania, United States. It is known for research contribution in the topics: Population & Osteoblast. The organization has 1694 authors who have published 2038 publications receiving 87149 citations.


Papers
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Journal ArticleDOI
TL;DR: A 2D lattice model for crystal dissolution is considered and it is shown that the steady-state surface topography in this model system is a function of, at most, two variables, which means that relative rates can be determined from two parameters characterizing the topography of a surface provided that the two parameters are independent of one another.
Abstract: The topography of a reactive surface contains information about the reactions that form or modify the surface and, therefore, it should be possible to characterize reactivity using topography parameters such as surface area, roughness, or fractal dimension. As a test of this idea, we consider a two-dimensional (2D) lattice model for crystal dissolution and examine a suite of topography parameters to determine which may be useful for predicting rates and mechanisms of dissolution. The model is based on the assumption that the reactivity of a surface site decreases with the number of nearest neighbors. We show that the steady-state surface topography in our model system is a function of, at most, two variables: the ratio of the rate of loss of sites with two neighbors versus three neighbors (d(2)/d(3)) and the ratio of the rate of loss of sites with one neighbor versus three neighbors (d(1)/d(3)). This means that relative rates can be determined from two parameters characterizing the topography of a surface provided that the two parameters are independent of one another. It also means that absolute rates cannot be determined from measurements of surface topography alone. To identify independent sets of topography parameters, we simulated surfaces from a broad range of d(1)/d(3) and d(2)/d(3) and computed a suite of common topography parameters for each surface. Our results indicate that the fractal dimension D and the average spacing between steps, E[s], can serve to uniquely determine d(1)/d(3) and d(2)/d(3) provided that sufficiently strong correlations exist between the steps. Sufficiently strong correlations exist in our model system when D>1.5 (which corresponds to D>2.5 for real 3D reactive surfaces). When steps are uncorrelated, surface topography becomes independent of step retreat rate and D is equal to 1.5. Under these conditions, measures of surface topography are not independent and any single topography parameter contains all of the available mechanistic information about the surface. Our results also indicate that root-mean-square roughness cannot be used to reliably characterize the surface topography of fractal surfaces because it is an inherently noisy parameter for such surfaces with the scale of the noise being independent of length scale.

4 citations

Journal ArticleDOI
TL;DR: This paper evaluated the question of whether students benefit or are harmed by multiple choice exams, and concluded that students benefit from the advice on test-taking strategies and are not always well informed by research.
Abstract: Multiple choice exams are ubiquitous, but advice on test-taking strategies varies and is not always well informed by research. This study evaluated the question of whether students benefit or are h...

4 citations

Journal ArticleDOI
TL;DR: This article found that TE patients showed a complete loss of EpCam expression in enterocytes and biliary epithelial cells, while the normal and TPN groups showed basolateral expression, indicating a defect in the apical-basal polarity of cholangiocytes.
Abstract: Background & aims Tufting enteropathy (TE) is a rare congenital disorder often caused by mutations in the gene encoding epithelial cell adhesion molecule (EpCam) The disease leads to diarrhea, intestinal failure and dependence on total parenteral nutrition (TPN) These patients often have liver impairments, but the pathology and mechanism of the damage are not well understood We evaluated liver biopsies from TE patients to understand the pathophysiology Methods We identified three patients with TE who underwent liver biopsy Two normal controls and 45 patients on TPN secondary to short gut syndrome were selected for comparison (5 were age- and TPN duration-matched to the TE patients) Results We found that all TE patients showed a complete loss of EpCam expression in enterocytes and biliary epithelial cells, while the normal and TPN groups show basolateral expression Histologically TE patients showed ductopenia, which was not seen in control groups E-cadherin and β-catenin are normally located along the lateral membrane of biliary epithelial cells However, they were relocated to the apical membrane in TE patients, indicating a defect in the apical-basal polarity of cholangiocytes We examined hepatic reparative cells and found near absence of hepatic progenitor cells and intermediate hepatobiliary cells with mild reactive ductular cells in TE patients Conclusion Our findings show that TE is associated with disrupted polarity of cholangiocyte and ductopenia We demonstrate for the first time a role of EpCam in the maintenance of integrity of biliary epithelium We also provided evidence for a disrupted development of hepatic reparative cells

4 citations

Journal ArticleDOI
TL;DR: To investigate mechanisms involved in the effects of CTGF on osteoblastic cell differentiation, CTGF modifies the activity of nuclear factor of activated T‐cells (NFATc) 1, a transcription factor that cooperates with osterix in the formation of new bone.
Abstract: Connective tissue growth factor (CTGF), a member of the Cyr 61, CTGF, Nov (CCN) family of proteins, regulates multiple cellular functions. Overexpression of CTGF in vivo causes osteopenia, but in vitro CTGF can induce osteoblastogenesis. To investigate mechanisms involved in the effects of CTGF on osteoblastic cell differentiation, we examined whether CTGF modifies the activity of nuclear factor of activated T-cells (NFATc) 1, a transcription factor that cooperates with osterix in the formation of new bone. CTGF increased the transactivation of a transiently transfected reporter construct, where 9 NFAT binding sites direct the expression of luciferase (9xNFAT-Luc) and the activity of the Regulators of calcineurin 1 exon 4 (Rcan1.4) promoter, an NFAT target gene. We postulated that CTGF could modify the phosphorylation of NFAT by regulating glycogen synthase kinase 3beta (GSK3beta). CTGF increased the mRNA levels of Protein kinase cyclic guanosine monophosphate (cGMP) dependent type II (Prkg2), the gene encoding for cGMP dependent protein kinase II (cGKII) which phosphorylates GSK3beta. Accordingly, CTGF induced GSK3beta phosphorylation and decreased the active pool of GSK3beta, a kinase that phosphorylates NFAT and leads to its nuclear export. As a consequence, CTGF favored the nuclear localization of NFATc1. Downregulation of PRKG2 by RNA interference reversed the effect of CTGF on the transactivation of the 9xNFAT reporter construct and the Rcan 1.4 promoter, confirming the role of cGKII in the activation of NFAT by CTGF. In conclusion, CTGF enhances NFAT signaling through the induction of cGKII and the phosphorylation of GSK3beta.

4 citations

Journal ArticleDOI
TL;DR: There has been a significant decline in HIV infections among young pregnant women attending ANC clinics in Tanzania since 2001 and this study indicates that ANC surveillance among pregnant women over time can provide useful estimates of HIV situation between the population surveys.
Abstract: Background: The Tanzania National AIDS Control Programme has established HIV sentinel surveillance among antenatal clinic (ANC) attendees as one of the methods for collecting data on HIV prevalence. This article provides trends on HIV prevalence for 92 sentinel sites that have constantly been part of the surveillance system since 2001 and have participated in at least three consecutive rounds. Method: The surveillance population included all pregnant women aged 15–49 years who were attending a selected sentinel ANC site for the first time for any pregnancy between 2001 and 2011. Serial testing for HIV infection was done anonymously by detecting for the presence of IgG antibodies to HIV on dried blood spot (DBS) specimens. HIV trends were calculated taking into account random effects from sites on the following variables: region, sites and socio-demographic characteristics defined as age, marital status, parity, education level and duration of stay at present residence. Results: Overall, there was a significant decline in HIV prevalence from 9.6% in 2001 to 5.6% in 2011 (p<0.01). Specifically, the HIV prevalence among 15-24 years’ pregnant women significantly declined from 7.8% in 2001/2002 to 4% in 2011 (p<0.01). The decline in HIV prevalence occurred irrespective of residence, marital status, education level or previous pregnancies. Conclusion: There has been a significant decline in HIV infections among young pregnant women attending ANC clinics in Tanzania since 2001. This study also indicates that ANC surveillance among pregnant women over time can provide useful estimates of HIV situation between the population surveys.

4 citations


Authors

Showing all 1697 results

NameH-indexPapersCitations
Steven M. Greenberg10548844587
Linus Pauling10053663412
Ernesto Canalis9833130085
John S. Gottdiener9431649248
Dalane W. Kitzman9347436501
Joseph F. Polak9140638083
Charles A. Boucher9054931769
Lawrence G. Raisz8231526147
Julius M. Gardin7625338063
Jeffrey S. Hyams7235722166
James J. Vredenburgh6528018037
Michael Centrella6212011936
Nathaniel Reichek6224822847
Gerard P. Aurigemma5921217127
Thomas L. McCarthy5710710167
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20234
20228
2021146
2020133
2019126
201897