DEVELOPMENT OF NOVEL POLYMERIC MATERIALS FOR THEIR APPLICATION IN MONITORING AND REMEDIATION OF ENVIRONMENTAL POLLUTANTS

Remediation of environmental pollutants from water is one of the major challenges in the 21st century. Utilizing novel polymeric materials to accomplish this challenge has garnered a lot of interest in recent times. Flexibility in synthesizing as well as functionalizing makes them attractive for their application in pollutant remediation. This work is based on development and characterization of novel crosslinked polymeric as well as linear polymeric materials from biphenyl-based monomers, biphenyl based crosslinker and a temperature responsive monomer (Nisopropylacrylamide (NIPAAm)) for their application in remediation of toxic pollutants such as polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and iron oxide nanoparticle (IONP) waste. First, we developed novel crosslinked polymers with the help of biphenyl-based monomers and crosslinker that have high affinity towards PCBs due the presence of pi-pi stacking interactions. Novel monomers and crosslinkers were initially synthesized by acrylation of 4,4-dihydroxybiphenyl, 4-phenylphenol, 2-phenylphenol, and the acrylated forms were identified as 44BDA, 4PPMA, 2PPMA respectively. These monomers were characterized by various techniques, including differential scanning calorimetry (DSC) for their melting temperature/freezing temperature, NMR and FTIR to confirm their structure. Subsequently, crosslinked polymer films were synthesized using 4PPMA, and 2PPMA as monomers and crosslinked with different amounts of 44BDA. These films were then characterized by studying their swelling properties in different solvents as well as their mechanical strength through the determination of their compression modulus. These developed materials were compared with polyethylene (LDPE) to test their efficacy as a passive sampling material in real world sediment. The biphenyl polymers along with LDPE were deployed into sediments with known PCB and PAHs concentration. PCBs/PAHs were allowed to bind on them, these polymers were then retrieved to analyze the amount of PCBs and PAHs bound on them at different time interval to study the binding kinetics and compare the equilibrium binding amounts between LDPE and biphenyl based polymers. We also developed novel polymers by incorporating the biphenyl moiety monomers (2PPMA,4PPMA) into a PNIPAAm network to develop a physically crosslink network which crosslinks due to the presence of pi-pi stacking interaction. The developed polymer were then tested for their molecular weight, swelling properties and mechanical properties. Derivatives of these novel physically crosslinked system were used to flocculate IONPs from water. These polymers were first characterized for their lower critical solution temperature, their molecular weight as well as their zeta potential. Iron oxide nanoparticles were flocculated from a suspension by addition of these polymers as well as salt to the solution. The flocculation efficiency was studied by varying the polymer concentration, salt concentration as well as IONP concentration. Overall, functionalized polymers can be widely used for remediating toxic pollutants from the environment

Hygroscopic growth and cloud condensation nuclei activity of fresh and chemically-aged biomass-pyrolyzed organic aerosol

Biomass burning is one of the prominent contributors of organic aerosols and cloud condensation nuclei (CCN) in the atmosphere. Aerosol-cloud interactions contribute to uncertainties in estimates of climate forcing, not only because of the complexities in their initial size and chemical composition, but also because of transformations (aging) they undergo in the atmosphere upon exposure to reactive species (e.g., NH3 and O3). This study presents results of bench-scale experiments on biomass pyrolysis organic carbon (OC) particles to determine its hygroscopic growth at sub-saturated relative humidities (RH) as well as CCN activity and droplet sizes at super-saturated humidity. This thesis investigates changes in these properties upon controlled, atmospherically-relevant exposures of NH3, O3 and RH. Measurements of hygroscopic growth and CCN activity are analyzed using κ-Köhler theory to calculate representative hygroscopicity parameters, κGF and κCCN, respectively (c.f. Petters and Kreidenweis 2007). Discrepancies as large as factors of three between κGF and κCCN suggest that approximating the surface tension of solution droplets to that of pure water, as assumed in κ- Köhler theory, overestimates the CCN activity of these complex organic particles. A possible evidence of the presence of surfactants is the formation of more than one hygroscopic activation modes in size-resolved CCN activation curves. While no change in κGF is observed after a 9 day- equivalent of atmospheric NH3-aging, a 72% increase in κCCN of OC particles suggests the presence of organic acidic groups in sufficient amount to influence the overall hygroscopic behavior of the particles. Chemical aging with O3 has no measurable impact on the κGF and κCCN of OC particles. My results suggest the possibility that oxidation of gas-phase volatile organic compounds in the aerosol by O3 causes them to condense as films on pre-existing particles. An evidence of such film formation is the reduced diameters of droplets exiting a cloud chamber, wherein the CCN have been exposed to a controlled supersaturation ratio for a fixed amount of time. We find that the possible participation of water taken up during aging at controlled relative humidity conditions does not affect hygroscopicity of OC particles. The results in this thesis are consistent with previously published results of effects of chemical aging with NH3 and O3 on the hygroscopicity of organic particles. Moreover, while previous studies have investigated organic particles of controlled initial composition, the results presented here apply to biomass pyrolysis OC particles. This thesis aids in understanding the important chemical aging mechanisms that organic particles emitted from pyrolysis of biomass could undergo, leading to their possibly increased hygroscopicity in the atmosphere

Disordered Phase in Ising and Metastability in Cellular Potts Models Hint at Glassy Dynamics

In this paper, quantum algorithms are to be used to simulate glassy systems in toy models. To look for glassy behavior, the energy landscape and spin configurations of the transverse field Ising model in a longitudinal field are studied. The Variational Quantum Eigensolver (VQE) is used to obtain the ground-state energies and corresponding eigenstates for a $6 \times 6$ Ising lattice using 36 qubits and a 1-dimensional Ising chain of length 25. For the $8 \times 8$ Cellular Potts model, the original Hamiltonian is converted to an Ising formulation for the VQE to reduce to its ground state. The energy change during minimization is carefully analyzed to find whether the effects of interfacial tension among cells could probably induce glassiness in the cell system

Stent vs. Stent-less Ileal Conduits After Radical Cystectomies: Is There Difference In Early Postoperative Outcomes?

Placing ureteral stents at the ureteroileal anastomosis for radical cystectomy with ileal conduit (RCIC) diversion has long been common practice, which has recently been called into question. In this study, we aim to investigate the difference in 30-day outcomes between patients who did and did not receive ureteral stents after RCIC.https://jdc.jefferson.edu/urologyfposters/1003/thumbnail.jp

Avoidant Restrictive Food Intake Disorder Prevalent Among Patients With Inflammatory Bowel Disease

Background & Aims Inflammatory bowel disease (IBD) patients alter their dietary behaviors to reduce disease-related symptoms, avoid feared food triggers, and control inflammation. This study aimed to estimate the prevalence of avoidant/restrictive food intake disorder (ARFID), evaluate risk factors, and examine the association with risk of malnutrition in patients with IBD. Methods This cross-sectional study recruited adult patients with IBD from an ambulatory clinic. ARFID risk was measured using the Nine-Item ARFID Screen. Nutritional risk was measured with the Patient Generated-Subjective Global Assessment. Logistic regression models were used to evaluate the association between clinical characteristics and a positive ARFID risk screen. Patient demographics, disease characteristics, and medical history were abstracted from medical records. Results Of the 161 participants (Crohn’s disease, 45.3%; ulcerative colitis, 51.6%; IBD-unclassified, 3.1%), 28 (17%) had a positive ARFID risk score (≥24). Most participants (92%) reported avoiding 1 or more foods while having active symptoms, and 74% continued to avoid 1 or more foods even in the absence of symptoms. Active symptoms (odds ratio, 5.35; 95% confidence interval, 1.91–15.01) and inflammation (odds ratio, 3.31; 95% confidence interval, 1.06–10.29) were significantly associated with positive ARFID risk. Patients with a positive ARFID risk screen were significantly more likely to be at risk for malnutrition (60.7% vs 15.8%; P \u3c .01). Conclusions Avoidant eating behaviors are common in IBD patients, even when in clinical remission. Patients who exhibit active symptoms and/or inflammation should be screened for ARFID risk, with referrals to registered dietitians to help monitor and address disordered eating behaviors and malnutrition risk

Patient Factors Impacting Perioperative Outcomes for T1b-T2 Localized Renal Cell Carcinoma May Guide Decision for Partial versus Radical Nephrectomy

There remains debate surrounding partial (PN) versus radical nephrectomy (RN) for T1b-T2 renal cell carcinoma (RCC). PN offers nephron-sparing benefits but involves increased perioperative complications. RN putatively maximizes oncologic benefit with complex tumors. We analyzed newly available nephrectomy-specific NSQIP data to elucidate predictors of perioperative outcomes in localized T1b-T2 RCC. We identified 2094 patients undergoing nephrectomy between 2019-2020. Captured variables include surgical procedure and approach, staging, comorbidities, prophylaxis, peri-operative complications, reoperations, and readmissions. 816 patients received PN while 1278 received RN. Reoperation rates were comparable; however, PN patients more commonly experienced 30-day readmissions (7.0% vs. 4.7%, p = 0.026), bleeds (9.19% vs. 5.56%, p = 0.001), renal failure requiring dialysis (1.23% vs. 0.31%, p = 0.013) and urine leak or fistulae (1.10% vs. 0.31%, p = 0.025). Infectious, pulmonary, cardiac, and venothromboembolic event rates were comparable. Robotic surgery reduced occurrence of various complications, readmissions, and reoperations. PN remained predictive of all four complications upon multivariable adjustment. Several comorbidities were predictive of complications including bleeds and readmissions. This population-based cohort explicates perioperative outcomes following nephrectomy for pT1b-T2 RCC. Significant associations between PN, patient-specific factors, and complications were identified. Risk stratification may inform management to improve post-operative quality of life (QOL) and RCC outcomes