Nicholls State University

This study utilized a dynamic cross-linking algorithm to formulate a chemical cross-linked hydrogel model of poly(N-isopropylacrylamide) (PNIPAM) with N, N’-methylenebisacrylamide (BIS). Molecular dynamics (MD) simulations were conducted to investigate the temperature sensitivity and ibuprofen release mechanism of this hydrogel under varying cross-linking degrees and water contents. The low critical solution temperature (LCST) of the hydrogel was determined based on changes in solvent-accessible surface area (SASA) and hydrogen bond count. The LCST was found to be between 300 and 310 K. As the temperature increased, both SASA and hydrogen bond counts generally exhibited a gradual decrease. However, near the LCST, polymer chain collapse temporarily exposed the hydrophilic groups of the PNIPAM, forming hydrophilic regions that increased the contact area with water. This led to a transient increase in SASA (8% higher than that before 300 K) and hydrogen bond counts (6.25% higher than that at 290 K). Concurrently, Young’s modulus of the PNIPAM hydrogel was found to decrease with increasing water content (from 3.11 GPa to 2.59 GPa, representing a 16.7% decrease when water content increased from 0% to 50% for 80% cross-linking degree) and increase with rising cross-linking density (from 2.02 GPa to 2.94 GPa, representing a 45.5% increase when the cross-linking degree increased from 0% to 80% for 20% water content). These findings indicate that enhancing cross-linking density is an effective strategy for improving the hydrogel’s mechanical properties. A PNIPAM–ibuprofen delivery model was constructed and molecular dynamics (MD) simulations were conducted, revealing temperature dependence release behavior. Below the LCST, the PNIPAM hydrogel remains in a highly swollen state (PNIPAM single-chain radius of gyration, Rg = 0.64 nm at 290 K), with ibuprofen molecules adsorbed within the PNIPAM polymer chain network. Conversely, above the LCST, PNIPAM undergoes phase separation (Rg decreases to 0.56 nm at 320 K, representing a 12.5% decrease), resulting in volume contraction (cavity volume reduced by 35%) and disruption of the hydrogen bond network. This process results in the release of ibuprofen molecules, accompanied by an increase in their diffusion coefficient from 1.3817 × 10−9 (280 K) to 4.2847 × 10−9 m2/s (320 K). Concurrently, the interaction energy with PNIPAM experiences a decline, from −126.72 kcal/mol to −108.69 kcal/mol. The findings of this study provide insights into the optimization of the structural stability of ibuprofen delivery carriers.

Faculty burnout is a pervasive concern for higher education institutions, with instructors reporting heightened exhaustion, increased cynicism toward the workplace, and reduced task efficacy. This study examines the potential of instructor-student rapport and out-of-class communication (OCC) as resources to mitigate faculty burnout, using the Job Demands–Resources (JD-R) model as a guiding framework. The results reveal that strong instructor-student rapport significantly reduces burnout, while OCC offers additional support. These findings highlight the importance of fostering relational dynamics between faculty and students as a proactive strategy to address burnout and elevate faculty well-being, satisfaction, and retention in higher education.

Structural equation modeling (SEM) has become one of the most commonly used tools in management research, yet researchers frequently encounter methodological challenges that can compromise the validity of their findings. This symposium presents three methodological papers that offer empirically validated solutions to common challenges in latent variable modeling. The paper by Williams, Culpepper, and Castille evaluates competing approaches for model selection using the RMSEA-P fit index, providing evidence-based guidance for choosing between Traditional and Sequential Model Comparison strategies. Next, Choi and colleagues introduce a novel Pseudo-Augmentation strategy to address underidentification issues in bifactor predictive models, demonstrating its effectiveness through Monte Carlo simulations and empirical examples. Finally, Hanna presents a comprehensive empirical investigation of competing parceling approaches for multidimensional constructs, illuminating how parceling decisions impact model fit. Together, these works provide additional methodological insight into common SEM challenges by providing researchers with empirically supported strategies for improving model selection, addressing identification issues, and making informed decisions about parameter reduction in structural equation modeling. A Comparison of Latent Variable Model Selection Approaches Using the RMSEA-P Author: Larry J. Williams; Texas Tech University Author: Steven Culpepper; Author: Christopher Castille; Nicholls State University A Pseudo-Augmentation Strategy to Address Underidentification in Bifactor Predictive Models Author: Jinsoo Choi; University of Illinois at Urbana-Champaign Author: Bo Zhang; University of Illinois at Urbana-Champaign Author: Susu Zhang; University of Illinois at Urbana-Champaign Author: Yonguk Park; Kyungnam University A Test of Parceling Approaches with Multidimensional Constructs and Their Model Fit Consequences Author: Andrew A. Hanna; University of Nebraska-Lincoln

The activation of chalcogenoglycosides for O-glycosylation typically involves strong electrophiles requiring low temperature. Herein, we demonstrate that visible-light irradiation of selenoglycosides in the presence of Umemoto's reagent results in often high-yielding O-glycosylation. We provide evidence that this process is mediated by a novel mode of reactivity, specifically photoinduced electron transfer within a chalcogen-bonded complex.

Abstract A photochemical [2 + 2] cycloaddition between cyclopentene-1-one and 1,1-dimethoxyethylene was effectively utilized to synthesize a key bicyclic intermediate in the preparation of tricyclic iridoid-inspired scaffolds. The regioselective outcome of the cycloadduct was confirmed through ¹H NMR and subsequent chemical reactivity studies, indicating that the methoxy groups do not occupy positions β to the carbonyl. Following this, hydrolysis of the cycloadduct yielded a diketone in an excellent yield of 85%, which was subsequently subjected to Baeyer–Villiger oxidation, resulting in a fused γ-lactone with a yield of 64%. Structural elucidation of the intermediates and the final product was conducted using NMR, IR, and mass spectrometry techniques. This photochemical synthetic pathway offers a concise approach to bioinspired tricyclic architectures that may hold significance in natural product chemistry and the design of neuroactive compounds.

Antibiotic resistance has become a significant public health concern due to the improper consumption and disposal of antibiotics. Improper handling often leads to selective pressure among bacteria that can lead to antibiotic resistance. Terrebonne parish in Louisiana being heavily populated, is dependent on Bayou for its seafood, recreational activities, transportation, and source of living. The water quality of Bayou Terrebonne and Bayou Petite Calliou has never been monitored before. The purpose of this study was to monitor the water quality of Bayou Terrebonne and Bayou Petite Calliou. Four sites along the bayous were monitored for water chemistry, total and fecal coliforms, and antibiotic resistance. The water samples were collected in triplicate and checked for the presence of antibiotic-resistant bacteria, coliforms bacteria, and the levels of organic carbon, nitrogen, ammonia, sulfate, and phosphate. The antibiotics tested on samples includes Tetracycline, Penicillin, Amoxicillin, Sulfamethoxazole-Trimethoprim, Bacitracin, Streptomycin Meropenem, and Erythromycin. The results showed that the bayou meets the criteria set by the Louisiana Department of Environmental Quality (LDEQ) for water chemistry except for sulfate concentration. The amount of total and fecal coliform exceeded the water quality standard due to fecal contamination from the discharge of untreated and/or under treated domestic wastewater from failing septic tanks and individual household sewage treatment systems along the bayous. Many antibiotic resistant bacteria and resistance genes were isolated from the water samples. The water is heavily impaired by the fecal contamination and the antibiotic resistant bacteria due to improper disposal of individual sewage treatment plant from households along the bayous.