Many small molecules can self-assemble by non-covalent interactions into fibrous networks and thereby induce gelation of organic liquids. However, no capability currently exists to predict whether a molecule in a given solvent will form a gel, a low-viscosity solution (sol), or an insoluble precipitate. Gelation has been recognized as a phenomenon that reflects a balance between solubility and insolubility; however, the distinction between these regimes has not been quantified in a systematic fashion. In this work, we focus on a well-known gelator, 1,3:2,4-dibenzylidene sorbitol (DBS), and study its self-assembly in various solvents. From these data, we build a framework for DBS gelation based on Hansen solubility parameters (HSPs). While the HSPs for DBS are not known a priori, the HSPs are available for each solvent and they quantify the solvent's ability to interact via dispersion, dipole-dipole, and hydrogen bonding interactions. Using the three HSPs, we construct three-dimensional plots showing regions of solubility (S), slow gelation (SG), instant gelation (IG), and insolubility (I) for DBS in the different solvents at a given temperature and concentration. Our principal finding is that the above regions radiate out as concentric shells: i.e., a central solubility (S) sphere, followed in order by spheres corresponding to SG, IG, and I regions. The distance (R0) from the origin of the central sphere quantifies the incompatibility between DBS and a solvent-the larger this distance, the more incompatible the pair. The elastic modulus of the final gel increases with R0, while the time required for a super-saturated sol to form a gel decreases with R0. Importantly, if R0 is too small, the gels are weak, but if R0 is too large, insolubility occurs-thus, strong gels fall within an optimal window of incompatibility between the gelator and the solvent. Our approach can be used to design organogels of desired strength and gelation time by judicious choice of a particular solvent or a blend of solvents. The above framework can be readily extended to many other gelators, including those with molecular structures very different from that of DBS. We have developed a MATLAB program that will be freely available (upon request) to the scientific community to replicate and extend this approach to other gelators of interest.

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Background: Bariatric surgery (BS) has been proven to be effective in the treatment of obesity and weight-related diseases, but the anatomic changes after BS make endoscopic retrograde cholangiopancreatography (ERCP) technically challenging. This study aims to assess the safety and clinical outcomes of ERCP in patients with previous BS. Materials and Methods:The National Inpatient Sample from 2007 to 2013 was queried for hospitalizations of adults over 18 years of age with procedure diagnoses of ERCP. Those with prior BS were selected as cases and those without BS as controls. Case-control matching at a ratio of 1 case to 2 controls was performed based on sex, age, race, comorbidities, and obesity. The primary outcomes were inpatient mortality and ERCP-related complications. Multivariate regression analysis was used to identify independent risk factors associated to the primary outcomes.Results: A total of 1,068,862 weighted hospitalizations with ERCP procedure codes were identified. Of these, 6689 with BS were selected as cases, and 13,246 were matched as controls. The reason for hospital admission was most often biliary stone disease (60.7% vs. 55.5%), followed by malignancy (3.5% vs. 12.1%) and cholangitis (7.7% vs. 4.5%) with and without BS, P < 0.05. The BS group had lower rates of post-ERCP pancreatitis (0.1% vs. 1.3%), cholecystitis (0.1% vs. 0.3%), bleeding (1.0% vs. 1.4%), and inpatient mortality (0.2% vs. 0.5%), but had higher rates of cholangitis (5.0% vs. 3.7%) and systemic infections (6.2% vs. 4.8%), all P < 0.05.Conclusions: BS group had lower post-ERCP pancreatitis, cholecystitis and bleeding while had more cholangitis, and systemic infection compared with those without BS. Also, BS was independently associated with reduced inpatient mortality after adjusted for age, race, and comorbidity.

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Autoimmune hepatitis (AIH) is a form of liver inflammation in which immune cells target hepatocytes, inducing chronic inflammatory states. Bariatric surgery (BS) was shown to reduce inflammation in severely obese patients. We hypothesize that obese patients with AIH and BS have lower prevalence of liver-related complications and in-patient mortality compared to those without BS. The National Inpatient Sample from 2007 to 2013 was queried for hospitalizations of adults over 18 years of age with a diagnosis of AIH. Of those, hospitalizations with BS were selected as cases and those with morbid obesity as controls. Case-control 1:2 matching was done based on sex, age, race, and comorbidities. Primary outcomes were prevalence of liver-related complications and in-patient mortality. Independent risk factors of in-patient clinical outcomes were identified using multivariate regression analysis. From 137,834 hospitalizations with a diagnosis of AIH, 688 with BS were selected as cases, and 1295 were matched as controls. The prevalence of ascites was higher in the BS group compared to the control (odds ratio 1.73, 95% confidence interval (CI) 1.27–2.36). The prevalence of cirrhosis (36.8% vs 33.2%), portal hypertension (7.4% vs 10.0%), hepatic encephalopathy (10.6% vs 8.7%), and varices and variceal bleeding (3.9% vs 5.5%) was not statistically different from case controls, ( P > .05). BS was an independent risk factor for ascites (adjusted odds ratio (aOR) 1.87; 95% CI 1.36–2.56) and hepatic encephalopathy (aOR 1.42; 95% CI 1.03–1.97) but was an independent protective factor against in-patient mortality (aOR 0.21, 95% CI 0.08–0.55) once adjusted for age, sex, race, and comorbidities.