Learning Communities: A Sound Investment in Higher Education

University and college leaders are tasked with enhancing student outcomes with fewer resources. Student retention is one such key outcome of interest for many policy makers as well as for university administrators. Over the years, administrators have turned to High Impact Practices (HIPs) such as Learning Communities (LCs) to aid in retention. This quantitative study explores the impact LCs have on student retention at a large R1 university in the Midwest. Additionally, the financial return on investment in LCs at this institution is measured via tuition dollars generated from students who are retained as a result of their participation in a LC at the institution. Two key findings of this study are that LCs are positively associated with increased odds of student retention, and that investing in LCs makes good financial sense. Our research contributes to the scholarship on retention attributable to LCs and provides researchers and practitioners with a “template” to evaluate the efficacy of specific retention initiatives in relation to their financial return on investments.

A novel antioxidant ergothioneine PET radioligand for in vivo imaging applications

Ergothioneine (ERGO) is a rare amino acid mostly found in fungi, including mushrooms, with recognized antioxidant activity to protect tissues from damage by reactive oxygen species (ROS) components. Prior to this publication, the biodistribution of ERGO has been performed solely in vitro using extracted tissues. The aim of this study was to develop a feasible chemistry for the synthesis of an ERGO PET radioligand, [11C]ERGO, to facilitate in vivo study. The radioligand probe was synthesized with identical structure to ERGO by employing an orthogonal protection/deprotection approach. [11C]methylation of the precursor was performed via [11C]CH3OTf to provide [11C]ERGO radioligand. The [11C]ERGO was isolated by RP-HPLC with a molar activity of 690 TBq/mmol. To demonstrate the biodistribution of the radioligand, we administered approximately 37 MBq/0.1 mL in 5XFAD mice, a mouse model of Alzheimer’s disease via the tail vein. The distribution of ERGO in the brain was monitored using 90-min dynamic PET scans. The delivery and specific retention of [11C]ERGO in an LPS-mediated neuroinflammation mouse model was also demonstrated. For the pharmacokinetic study, the concentration of the compound in the serum started to decrease 10 min after injection while starting to distribute in other peripheral tissues. In particular, a significant amount of the compound was found in the eyes and small intestine. The radioligand was also distributed in several regions of the brain of 5XFAD mice, and the signal remained strong 30 min post-injection. This is the first time the biodistribution of this antioxidant and rare amino acid has been demonstrated in a preclinical mouse model in a highly sensitive and non-invasive manner.

Silver-coated monolitic silica column for separation of benzo[a]pyrene from petroleum

Monolithic silica solid-phase extraction column has been successfully applied for the rapid fractionation and subsequent gas chromatographic analysis of benzo[a]pyrene from the diesel and oil matrix. Due to π-π electronic interactions between silver nanoparticles on the sorbent surface and aromatic analyte specific retention was achieved. It was demonstrated that only 0.2 g of the sorbent and 6 ml of the organic solvent are enough for such separation.

Featural dynamics in morphosyntactic change

This chapter examines Icelandic Dative Substitution (DS) and argues that two of its diachronic side effects, referred to as Person-Specific Retention and an Elsewhere Condition Death Rattle, are explained by the way in which formal features constrain the trajectory of morphosyntactic change. The study is based on naturally occurring data and a recent language acquisition experiment and the analysis draws on weighted grammatical rules as well as Yang’s Tolerance Principle. It is argued that DS does not necessarily involve a change in the syntax, but should rather be viewed as a change in the interpretation of syntactic information at the interface with morphology, resulting in variability on the surface. The results are analyzed in the context of recent theories on specialization in linguistic change and the dynamics of variation in individuals.

Thermodynamic Properties Investigation of Process Volatile Organic Compounds (VOCs) and Its Transport Impact Factor in Oil Sands Management

This paper presents a new approach for the determination of volatile organic compounds (VOCs) characteristics and their migration influencing factors in oil sands management processes and reveals the relationship between different asphaltene content and different solvents. Specifically, thermodynamic (i.e., partitioning coefficients, Kr, specific retention volume, Vg, the activity coefficients, γ and enthalpy of solution, ΔH0) and their impact factors are discussed. Gas-liquid chromatography (GLC) experimental measurements were used as the test data. A range of solvents (nC5, iC5, nC6, nC7, and Toluene) has been tested in different asphalt contents (0, 2.56, 9.93, 36.86, 53.67 wt%). There are temperatures in the range of 333.2–393.2 K (with 10 K increase) were conducted, respectively. The dynamics properties of asphalt mixture are calculated, and the relation between dynamics properties of asphalt mixture and absolute temperature, asphalt content and solvent type is discussed. The results show that within the acceptable error range, partitioning coefficients, Kr, specific retention volume, Vg, and enthalpy of solution, ΔH0 and other thermodynamic properties have a good tendency to predict, they decrease with the increase in asphaltene content and temperature and increase with the increase in solute carbon number.

Metal-Templated Synthesis of Rigid and Conformationally Restricted Cyclic Bisporphyrins: Specific Retention Times on Cyanopropyl-Modified Silica Gel Column

A series of rigid and conformationally restricted cyclic bis(zinc porphyrin)s connected via 2,2’-bipyridine and phthalamide, isophthalamide, or terephthalamide moieties were prepared by metal-templated synthesis. The yields were significantly improved when...

Design and Implementation of the Array Logging Tool on Horizontal Production Logging

The measuring instruments have some errors in the measurement of high water cut production wells, and many domestic oil fields are also in high water cut state. The measured data from the conventional production logging instrument are all almost inaccurate. This project has designed a staggered probe array flow meter well logging apparatus based on the characteristic of electromagnetic wave specific retention meter that can fully cover the wellbore fluid and improve flow measurement accuracy. According to the application in horizontal wells, the accuracy of this measuring instrument now has been proved to be more than 90% and can meet the requirements of production logging interpretation in horizontal wells.

Investigation of the effects of starting pH, mass and retention time on biogas production using poultry droppings as feedstock

The effect of starting pH, mass and retention time on biogas production was studied using poultry droppings as the feedstock. A full factorial experiment was designed and performed with starting pH set at 5, 6, 7, 8 & 9 for feedstock mass of 100g and 200g at specific retention times. The results presented an optimal biogas yield at pH=7 with a volume of 722 and 1046cm3 while pH=5 had the least with 255 and 481 cm3 at 100g and 200g mass respectively. The starting pH, mass and retention time and the interaction of starting pH and mass had significant effect on biogas yield at 5% significance level. The R-Square value obtained from the analysis was 92.1%. Thereafter, a log-linear regression model for predicting biogas yield was generated and was found to provide adequate prediction given its MAPE value of 19.97. Keywords: Biogas Production, Mass, Poultry Droppings, Retention Time, Starting pH.