Enantiomeric separations on cyclodextrin-based and synthetic polymeric chiral stationary phases by high performance liquid chromatography and supercritical fluid chromatography

High performance liquid chromatography (HPLC) employing chiral stationary phases (CSPs) is the most popular and effective method for the separation of enantiomers. In this dissertation, the first chapter is an overview of chiral stationary phases for HPLC, which includes the structures, separation mechanisms, and applications of a variety of chiral stationary phases. The use of some chiral stationary phases in SFC also is discussed.;The next three chapters present the enantiomeric separations of chiral furans, isochromenes, and polycycles on cyclodextrin-based chiral stationary phases. The performance of chiral stationary phases for the separation of these analytes was compared. The effect of the mobile phase compositions and structures of the analytes on the chiral recognitions were discussed.;Chapter 5 through chapter 7 focuses mainly on the development and evaluation of new synthetic polymeric chiral stationary phases. First, the enantiomeric separation abilities of a new polymeric chiral stationary phase based on the monomer N,N\u27-(1S,2S)-1,2-cyclohexanediyl-bis-2-propenamide was screened with 200 racemic samples. The enantiomeric separations obtained were optimized. The mobile phase compositions and a mobile phase additive (trifluoroacetic acid) were evaluated and the chiral recognition mechanism was discussed. The new CSP showed high sample loading capacity. Then, we developed two new synthetic polymeric CSPs with two other monomers, which are polymerible derivatives of trans-1,2-diphenylethylenediamine and trans-9,10-dihydro-9,10-ethanoanthracene-(11S,12S)-11,12-dicarboxylic acid. The two new CSPs also showed enantiomeric selectivities for a variety of chiral compounds and high sample loading capacity. The three new synthetic polymeric CSPs are complementary to each other.;Chapter 8 is a study on the use of the new synthetic polymeric CSPs with supercritical fluid eluents. The new CSPs also can separate many compounds using supercritical fluid chromatography (SFC). They showed high stabilities under SFC conditions. Compared with HPLC, SFC provides much faster separations due to the high flow rates. For some analytes, better enantiomeric separations were observed with SFC due to the better separation efficiencies

Clinical Support Personnel in the U.S. Hospitals: Job Trends from 2010-2014

The use of various forms of Clinical Support Personnel (CSP), who perform healthcare tasks under the supervision of registered nurses and other licensed healthcare providers has been used as a primary strategy for managing professional shortages (Huston, 1996; Zimmerman, 2000), while at the same time reducing costs (Orne, Garland, O’Hara, Perfetto, & Stielau, 1998; Keenan, 2003). The purpose of this analysis is to better understand how hospitals are using CSP, and to explore changes that may have occurred since the 2010 passage of the Affordable Care Act. We use the term CSP to refer to a portion of the allied health workforce who are hospital-based clinical support personne

The Changing Composition and Capacity of Medicare Providers, 2012-2015

Objective: Over the past decade, U.S. medical school enrollment has increased nearly 30 percent, and the growth in mid-level new graduates was even faster. Many of these new graduates are currently serving the large and growing Medicare population. Yet, little evidence so far has documented the workforce that are serving Medicare population. In the anticipation of physician supply shortages, it is important to understand who are taking care of Medicare population recently, and whether there are changes in the overall capacity and patient risk profiles of Medicare providers. Methods: Data were from 2012-2015 Medicare Physician and Other Supplier Aggregate Tables at the Centers for Medicare & Medicaid Services website, which contain information on utilization, payment, and procedures provided to more than 10 Medicare Part B beneficiaries by U.S. physicians and nurses. We identified primary care physicians (i.e., family practice, internal medicine, general practitioners, and geriatric medicine), specialists, and mid-level providers (e.g., nurse practitioners, physician assistants, etc.) based on self-reported provider type in the data. We conducted trend analysis to examine the changes in the proportion of physicians and mid-level providers over time, and also compared utilization, payment amount, and patient risk profiles of physicians and nurses between 2012 and 2015, respectively. Findings: Over the study period, the number of providers with more than 10 Medicare patients increased from 709,982 in 2012 to 782,836 in 2015. The proportion of both primary care physicians and specialists declined consistently, while in contrast, the proportion of mid-level providers increased correspondingly, from 20% in 2012 to 24% in 2015. Compared to 2012, Physicians in 2015 served fewer Medicare patients, but provided more services to beneficiaries, and had no changes in payment received than in 2015. In contrast, mid-level providers served more patients, provided more services per patient, and received higher payments in 2015 than in 2012. Both physicians and mid-level providers served more patients diagnosed with depression, asthma, chronic kidney disease, and stroke in 2015 than in 2012. Conclusion: Medicare provider composition has been changing in recent years, where mid-level providers are playing an increasing role in serving Medicare beneficiaries. State legislatures and policymakers may consider expanding scope-of-practice for mid-level providers and also weigh the importance of innovating new payment policy to better reimburse mid-level providers. Future research is needed to compare the capacity of new and existing providers and the relationship between year of practicing and capacity building to serve more Medicare patients

Genetic variations underlying Gilbert syndrome and HBV infection outcomes: a cross-sectional study

Background: Constant cellular damage causes a poor prognosis of hepatitis B virus (HBV) infection. Accumulating evidence indicates the cytoprotective properties of bilirubin. Here, we investigated the association of UDP glucuronosyltransferase family 1 member A1 (UGT1A1), the genetic cause of Gilbert syndrome (GS), a common condition of mild unconjugated bilirubinemia, with HBV infection outcomes.Methods: Patients (n = 2,792) with unconjugated hyperbilirubinemia were screened for HBV infection and host UGT1A1 variations in Ruijin Hospital from January 2015 to May 2023, and those with confirmed HBV exposure were included. The promoter/exons/adjacent intronic regions of UGT1A1 were sequenced. HBV infection outcomes were compared between hosts with wild-type and variant-type UGT1A1. The effect magnitudes of UGT1A1 variations were evaluated using three classification approaches.Results: In total, 175 patients with confirmed HBV exposure were recruited for final analysis. Age, gender, level of HBV serological markers, and antiviral treatment were comparable between UGT1A1 wild-type and disease-causing variation groups. Five known disease-causing mutations (UGT1A1*28, UGT1A1*6, UGT1A1*27, UGT1A1*63, and UGT1A1*7) were detected. The incidence of cirrhosis or hepatocellular carcinoma (LC/HCC) was significantly lower in UGT1A1 variant hosts than in UGT1A1 wild-type hosts (13.14% vs. 78.95%, p < 0.0001). The rarer the UGT1A1 variation a patient possessed, the higher the age at which LC/HCC was diagnosed (R = 0.34, p < 0.05). In contrast, patients without cirrhosis achieving HBsAg clearance were identified only in the UGT1A1 variant group (12.32% vs. 0%).Conclusion: The findings of this study provide insights into the association between preexisting genetically mild bilirubin elevation and viral infection outcome. We showed that the accumulation of UGT1A1 variants or the rarity of the variation is associated with a better prognosis, and the effect magnitude correlates with UGT1A1 deficiency. This study demonstrates the therapeutic potential of host UGT1A1 variations underlying GS against HBV infection outcomes

Nurse-Related Clinical Non-licensed Personnel in U.S. Hospitals and their Relationship with Nurse Staffing Levels

The use of the minimally trained, low wage clinical non-licensed personnel (CNLP), who perform clinical tasks under the supervision of registered nurses (RNs) or other licensed clinical providers, has been a primary strategy for hospitals both to manage professional shortages and reduce costs (Huston 1996; Zimmerman 2000; Orne et al. 1998; Keenan 2003). This study examined the nurse-related clinical non-licensed personnel (CNLP) staffing in U.S. hospitals between 2010 and 2014, in terms of their job categories, staffing trends, and relationship with registered nurse (RN) and licensed practical nurse (LPN) staffing. Key Questions: How were CNLPs used in hospitals in 2014 in comparison to registered nurse (RN) and licensed practice nurse (LPN) staffing levels? How did the variations in staffing for these CNLP groups correlate with RN and LPN staffing, as well as other factors such as patient mix? How have these relationships changed over time

A New Artificial Intelligence-Based Hierarchical K-Means Clustering Technique to Detect Addictive Twitter Activity

To stop the COVID-19 epidemic from spreading among their populations, several countries have implemented lockdowns. Students are being forced to stay at home during these lockdowns, which is causing them to use mobile phones, social media, and other digital technologies more frequently than ever. Their poor utilization of these digital tools may be detrimental to their emotional and mental health. In this study, we implement an Artificial Intelligence (AI) approach named Hierarchy-based K-Means Clustering (HKMC) algorithm to group individuals with comparable Twitter consumption habits to detect addictive Twitter activity during the epidemic. The effectiveness of the suggested HKMC is evaluated in terms of accuracy, precision, recall, and f1-score in respect to the association between students’ mental health and mobile phone dependency. Additionally, this study offers a comparative examination of both the suggested and existing procedures

Does ACO Adoption Change the Health Workforce Configuration in U.S. Hospitals?

Working with Premier, Inc., this study explored how participation in ACOs affects hospitals’ workforce assignment and configuration. The study 1) describes the differences in workforce characteristics in hospitals adopting versus not adopting an ACO model and 2) determines key changes in workforce before and after a hospital adopts an ACO model. Key Questions Hospitals with what types of workforce configuration are more likely to participate in an ACO? How do hospitals change their workforce after participating in an ACO? Do hospitals not yet participating in ACOs make similar/different changes to workforce as their peers in ACOs

An Improved Stability Criterion of Networked Control Systems

Abstract-The stability criterion of networked control systems with both the network-induced delays and data packet dropouts is investigated. A Lyapunov-Krasovskii functional candidate, which makes use of the information of the lower, upper bounds and the middle point of the time-varying networkinduced delay interval simultaneously, is proposed and a tighter bounding for an integral term of the delay is estimated to drive a less conservative stability condition for networked control systems. No redundant matrix variable is introduced. Finally, two numerical examples are given to show the effectiveness of the proposed stability criterion

Transmission infrared micro-spectroscopic study of individual human hair

Understanding the optical transmission property of human hair, especially in the infrared regime, is vital in physical, clinical, and biomedical research. However, the majority of infrared spectroscopy on human hair is performed in the reflection mode, which only probes the absorptance of the surface layer. The direct transmission spectrum of individual hair without horizontal cut offers a rapid and non-destructive test of the hair cortex but is less investigated experimentally due to the small size and strong absorption of the hair. In this work, we conduct transmission infrared micro-spectroscopic study on individual human hair. By utilizing direct measurements of the transmission spectrum using a Fourier-transform infrared microscope, the human hair is found to display prominent band filtering behavior. The high spatial resolution of infrared micro-spectroscopy further allows the comparison among different regions of hair. In a case study of adult-onset Still's disease, the corresponding infrared transmission exhibits systematic variations of spectral weight as the disease evolves. The geometry effect of the internal hair structure is further quantified using the finite-element simulation. The results imply that the variation of spectral weight may relate to the disordered microscopic structure variation of the hair cortex during the inflammatory attack. Our work reveals the potential of hair infrared transmission spectrum in tracing the variation of hair cortex retrospectively