Modeling the Morphodynamics of Coastal Responses to Extreme Events: What Shape Are We In?

This review focuses on recent advances in process-based numerical models of the impact of extreme storms on sandy coasts. Driven by larger-scale models of meteorology and hydrodynamics, these models simulate morphodynamics across the Sallenger storm-impact scale, including swash,collision, overwash, and inundation. Models are becoming both wider (as more processes are added) and deeper (as detailed physics replaces earlier parameterizations). Algorithms for wave-induced flows and sediment transport under shoaling waves are among the recent developments. Community and open-source models have become the norm. Observations of initial conditions (topography, land cover, and sediment characteristics) have become more detailed, and improvements in tropical cyclone and wave models provide forcing (winds, waves, surge, and upland flow) that is better resolved and more accurate, yielding commensurate improvements in model skill. We foresee that future storm-impact models will increasingly resolve individual waves, apply data assimilation, and be used in ensemble modeling modes to predict uncertainties.

Tropical cyclone rainbands can trigger meteotsunamis.

Tropical cyclones are one of the most destructive natural hazards and much of the damage and casualties they cause are flood-related. Accurate characterization and prediction of total water levels during extreme storms is necessary to minimize coastal impacts. While meteotsunamis are known to influence water levels and to produce severe consequences, their impacts during tropical cyclones are underappreciated. This study demonstrates that meteotsunami waves commonly occur during tropical cyclones, and that they can contribute significantly to total water levels. We use an idealized coupled ocean-atmosphere-wave numerical model to analyze tropical cyclone-induced meteotsunami generation and propagation mechanisms. We show that the most extreme meteotsunami events are triggered by inherent features of the structure of tropical cyclones: inner and outer spiral rainbands. While outer distant spiral rainbands produce single-peak meteotsunami waves, inner spiral rainbands trigger longer lasting wave trains on the front side of the tropical cyclones.

Non-Covalent Derivatives: Cocrystals and Eutectics.

Non-covalent derivatives (NCDs) are formed by incorporating one (or more) coformer molecule(s) into the matrix of a parent molecule via non-covalent forces. These forces can include ionic forces, Van der Waals forces, hydrogen bonding, lipophilic-lipophilic interactions and pi-pi interactions. NCDs, in both cocrystal and eutectic forms, possess properties that are unique to their supramolecular matrix. These properties include critical product performance factors such as solubility, stability and bioavailability. NCDs have been used to tailor materials for a variety of applications and have the potential to be used in an even broader range of materials and processes. NCDs can be prepared using little or no solvent and none of the reagents typical to synthetic modifications. Thus, NCDs represent a powerfully versatile, environmentally-friendly and cost-effective opportunity.

The science of green chemistry and its role in chemicals policy and educational reform.

Over the past 10 years, the science of green chemistry has continued to evolve and has been adopted in research labs in industry and academia. At the same time, new innovations in chemicals policy have widened opportunities for legislative action to protect human health and the environment. This article addresses the mechanisms by which the science of green chemistry and chemicals policy can work together to help attain a more sustainable future. It also speaks to the pitfalls of inappropriately merging these two, and explores how such a merger could inhibit the creation of sustainable technologies. Green chemistry's role in educational reform is discussed as a means for training students who are prepared to create truly sustainable technologies.

Association of Technetium(99m) MAG-3 renal scintigraphy with change in creatinine clearance following chemoradiation to the abdomen in patients with gastrointestinal malignancies.

BACKGROUND: Information on differential renal function following abdominal chemoradiation is limited. This study evaluated the association between renal function as measured by biochemical endpoints and scintigraphy and dose volume parameters in patients with gastrointestinal malignancies. MATERIALS AND METHODS: Patients who received abdominal chemoradiation between 2002 and 2009 were identified for this study. Technetium(99m) MAG-3 scintigraphy and laboratory data were obtained prior to and after chemoradiation in 6 month intervals. Factors assessed included age, gender, hypertension, diabetes, and dose volume parameters. Renal function was assessed by biochemical endpoints and renal scintigraphy. RESULTS: Significant reductions in relative renal function of the primarily irradiated kidney and creatinine clearance were seen. Split renal function decreased from 49.75% pre-radiation to 47.74% and 41.28% at 6-12 months and >12 months post-radiation (P=0.0184). Creatinine clearance declined from 90.67ml/min pre-radiation to 82.23ml/min and 74.54ml/min at 6-12 months and >12 months post-radiation (P<0.0001). Univariate analysis of patients who had at least one post-radiation renogram showed the percent volumes of the primarily irradiated kidney receiving ≥ 25 Gy (V(25)) and 40 Gy (V(40)) were significantly associated with ≥5% decrease in relative renal function (P=0.0387 and P=0.0438 respectively). CONCLUSION: Decline in split renal function using Technetium(99m) MAG-3 scintigraphy correlates with decrease in creatinine clearance and radiation dose-volume parameters following abdominal chemoradiation. Change in split perfusion can be detected as early as 6 months post-radiation. Scintigraphy may provide early determination and quantification of subclinical renal injury prior to clinical evidence of nephropathy.

Photosensitization of bioinspired thymine-containing polymers.

Here, we report a sensitization study on a family of water-soluble photopolymers based on thymine. The goal of this study was to determine whether the presence of sensitizer molecules would promote photocrosslinking/immobilization of the polymers using low-energy irradiation (520 nm) as compared to the UV irradiation (approximately 280 nm) necessary for the standard photoinduced process to take place. With the aid of Eosin Y Spirit Soluble (EY) as a sensitizer, water-soluble polystyrene copolymers of vinylbenzylthymine-vinylbenzyltriethylammonium chloride (VBT-VBA) were immobilized after exposure to visible irradiation. By exciting the sensitizer molecule in the presence of VBT copolymers at a wavelength where absorption by the latter does not occur, the triplet state of the sensitizer is generated in high yields, and consequently, polymer photocross-linking takes place. UV-vis spectroscopy has been used to study the effect of irradiation dose, copolymer composition, and sensitizer concentration on the photoreactivity of VBT polymers. These studies demonstrate the feasibility of using Eosin Y as a sensitizer to achieve the thymine photodimer formation, resulting in immobilization of VBT-VBA-EY films on PET substrate. This provides complementary information on photoinduced immobilization of VBT-VBA films that are crucial for developing new classes of environmentally benign materials and new energy-saving methods.

Effect of pH on the viscosity of titanium dioxide aqueous dispersions with carboxylic acids.

Dispersions of titanium dioxide nanoparticles with terephthalic acid, isophthalic acid, salicylic acid, benzoic acid, and pyridine-2,5-dicarboxylic acid were prepared by aqueous grinding. The pH of the dispersions was adjusted by adding either HCl or NaOH, and the viscosity of the dispersions was measured. It was found that the viscosity of the system depends strongly on pH. The qualitative interpretation of the results based on the DLVO theory is presented. The evidence of the effect of bridging interactions on the viscosity of titanium dioxide-dicarboxylic acid dispersions is discussed.

Core-bound polymeric micellar system based on photocrosslinking of thymine.

Bioinspired core-bound polymer micellar aggregates were synthesized by photocrosslinking thymine-functionalized cores using short UV irradiation; H-bonding between thymines in the core is also believed to increase micellar aggregate stability.

Bacteriostatic polymer film immobilization.

Coatings of quaternary ammonium tertiary structures (QUATS) copolymerized with 4-vinylbenzylthymine (VBT) exhibited high antimicrobial activity against Escherichia coli. Immobilization of QUATS improves environmental performance by preventing release of antibacterials to the environment, helping to preclude the emergence of resistant strains. The crosslinking immobilization scheme reported herein provides a more environmentally benign and more inexpensive synthesis than previously reported, thus reducing the use of solvents, energy, and production time. Development of water soluble, thymine-based photopolymers was inspired by the UV-induced 2pi + 2pi photocyclodimerization of thymine in DNA. Copolymers of 4-vinylbenzylthymine and trimethylammonium chloride, triethylammonium chloride, or dimethyloctylammonium chloride were synthesized in different monomer ratios. The antibacterial properties were tested by coating VBT:QUATS in sterilized petri dishes, crosslinking under short UV light, spraying with aqueous suspensions of bacterial cells, air drying, and then applying agar media to promote bacterial growth. The plates were incubated for 24 h at 37 degrees C. The number of viable cells ranged from 17 to 0% growth. Immobilized VBT:QUAT copolymers are antiseptic surfaces that can be produced in an environmentally benign fashion.

Photo-cross-linked immobilization of polyelectrolytes for enzymatic construction of conductive nanocomposites.

Horseradish peroxidase has been demonstrated to catalyze the oxidative polymerization of aniline to form conductive polyaniline. This process is facilitated by the presence of a macromolecular template with sulfonic acid groups that provide a unique environment for the formation of the conducting polymer. Here we report the use of a photo-cross-linkable thymine-based polymer with phenylsulfonate groups as a templating substrate. This allows for an aqueous-based environmentally benign photopatterning of a conductive material. A description and results of this process are presented.