Saint Francis University

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.

Deformation of organic matter and its effect on pores in mud rocks

Abstract: Pores within organic matter (OM) are strongly linked to hydrocarbon generation and primary migration in fine-grained source rocks and are very important for evaluating hydrocarbon storage and flow in shale reservoirs. Thus, it is critical to clarify the features of OM-hosted pores and their evolution in organic-rich mud rocks. The OM in mud rocks, including kerogen and bitumen, is deformed when the original equilibrium stress conditions are altered. The OM deformation at the nano- or microscale has rarely been discussed because of the lack of unequivocal evidence. This research begins with examining the subsurface evolution of kerogen and bitumen, with emphasis on various features of pores hosted by bitumen. Evidence of OM deformation is documented in scanning electron microscope images of seven overmature samples from the lower Silurian Longmaxi Shale, Sichuan Basin. To aid in the understanding and analysis, OM deformation is classified into three types: type I deformation induced by one additional force, type II deformation induced by two additional forces acting on two locations of single OM particles, and type III deformation induced by three or more deforming forces acting at three or more locations of single OM particles. Thus, type I deformation is generally less complex than type II and III deformation. The OM particles subjected to type I deformation were analyzed quantitatively for parameters such as pore size, geometry, and long-axis orientation of elliptical pores. Deformation of OM enhances the robust heterogeneity of OM-hosted pores.

Variation of fetal nasal bone length in second-trimester fetuses according to race and ethnicity.

Abstract: Objective. The purpose of this study was to determine the influence of race and ethnicity on the expected nasal bone length (NBL) based on biparietal diameter (BPD) measured in second-trimester fetuses. Methods. We searched our ultrasound, obstetric, and cytogenetic databases for all second-trimester fetuses with measured NBLs. Fetuses with Down syndrome were identified and excluded from the analysis. Linear regression curves were generated for NBL by BPD according to race and ethnicity. Categories used were African American, Hispanic, Asian, and white. Analysis of variance was used to compare mean variation of observed from expected NBL by BPD according to race and ethnicity. Results. There were 717 fetuses with NBL-by-BPD pairs who were available for analysis in our population, including 139 African American, 58 Hispanic, 22 Asian, and 498 white fetuses. Nasal bone length was highly correlated with BPD for each race (P <.001). Mean variances of observed from expected NBL by BPD were statistically different according to race or ethnicity (P =.0092). Conclusions. Race and ethnicity significantly affect the mean regression line of expected NBL by BPD among fetuses in the second trimester. Genetic sonographic norms, therefore, appear to require race-and ethnicity-specific formulas for NBL.

Insulin-like growth factor I inhibits the transcription of collagenase 3 in osteoblast cultures.

Abstract: Insulin-like growth factor (IGF) I is an autocrine regulator of bone remodeling which inhibits bone collagen degradation and interstitial collagenase 3 mRNA levels. The mechanism of this inhibitory effect on collagenase 3 expression is not known. We tested the effects of IGF I on collagenase 3 gene expression in cultures of osteoblast-enriched cells from 22 day fetal rat calvariae (Ob cells) to determine whether transcriptional or posttranscriptional mechanisms were involved in the regulation of the collagenase 3 gene. IGF I at 10-100 nM caused a dose-dependent decrease in collagenase mRNA and protein levels. IGF I did not modify the half-life of collagenase 3 mRNA in transcriptionally arrested Ob cells, whereas it decreased the levels of interstitial collagenase 3 heterogeneous nuclear RNA. In addition, IGF I decreased the rates of transcription of the collagenase gene and the activity of a 2.1 kilobase collagenase 3 promoter construct transiently transfected into Ob cells. In conclusion, IGF I decreases the expression of collagenase 3 mRNA by transcriptional mechanisms.