SORAS - a simple arsenic removal process

The serious threat to the health of millions of people through consumption of arsenic-rich groundwater in Bangladesh calls for immediate action on various levels. One of these actions is be the development of a low-cost and simple arsenic removal method available to every household. The development of alternative water sources and/or the installation of larger arsenic removal units will take more time due to logistic and financial constraints. Currently existing small-scale arsenic removal procedures require chemicals that are either not easily available and/or affect water taste and odour. Solar oxidation and removal of arsenic (SORAS) is a simple method that uses irradiation of water with sunlight in PET- or other UV-A transparent bottles to reduce arsenic levels from drinking water. The SORAS method is based on photochemical oxidation of As(III) followed by precipitation or filtration of As(V) adsorbed on Fe(III)oxides as shown in Fig. 1. Groundwater in Bangladesh naturally contains Fe(II) and Fe(III) and therefore, SORAS could reduce arsenic contents and would be available to everyone at virtually no cost. It could be a water treatment method used at household level to treat small quantities of drinking water

SORAS - a simple arsenic removal process

The serious threat to the health of millions of people through consumption of arsenic-rich groundwater in Bangladesh calls for immediate action on various levels. One of these actions is be the development of a low-cost and simple arsenic removal method available to every household. The development of alternative water sources and/or the installation of larger arsenic removal units will take more time due to logistic and financial constraints. Currently existing small-scale arsenic removal procedures require chemicals that are either not easily available and/or affect water taste and odour. Solar oxidation and removal of arsenic (SORAS) is a simple method that uses irradiation of water with sunlight in PET- or other UV-A transparent bottles to reduce arsenic levels from drinking water. The SORAS method is based on photochemical oxidation of As(III) followed by precipitation or filtration of As(V) adsorbed on Fe(III)oxides as shown in Fig. 1. Groundwater in Bangladesh naturally contains Fe(II) and Fe(III) and therefore, SORAS could reduce arsenic contents and would be available to everyone at virtually no cost. It could be a water treatment method used at household level to treat small quantities of drinking water

The Ozone–Climate Penalty: Past, Present, and Future

Climate change is expected to increase global mean temperatures leading to higher tropospheric ozone (O₃) concentrations in already polluted regions, potentially eroding the benefits of expensive emission controls. The magnitude of the “O₃–climate penalty” has generally decreased over the past three decades, which makes future predictions for climate impacts on air quality uncertain. Researchers attribute historical reductions in the O₃–climate penalty to reductions in NO_<i>x</i> emissions but have so far not extended this theory into a quantitative prediction for future effects. Here, we show that a three-dimensional air quality model can be used to map the behavior of the O₃–climate penalty under varying NO_<i>x</i> and VOC emissions in both NO_<i>x</i>-limited and NO_<i>x</i>-saturated conditions in Central and Southern California, respectively. Simulations suggest that the planned emissions control program for O₃ precursors will not diminish the O₃–climate penalty to zero as some observational studies might imply. The results further demonstrate that in a NO_<i>x</i>-limited air basin, NO_<i>x</i> control strategies alone are sufficient to both decrease the O₃–climate penalty and mitigate O₃ pollution, while in a NO_<i>x</i>-saturated air basin, a modified emissions control plan that carefully chooses reductions in both NO_<i>x</i> and VOC emissions may be necessary to eliminate the O₃–climate penalty while simultaneously reducing base case O₃ concentrations to desired levels. Additional modeling is needed to determine the behavior of the O₃–climate penalty as NO_<i>x</i> and VOC emissions evolve in other regions

Curvature-Coupled Hydration of Semicrystalline Polymer Amphiphiles Yields flexible Worm Micelles but Favors Rigid Vesicles: Polycaprolactone-Based Block Copolymers

Crystallization processes are in general sensitive to detailed conditions, but the present understanding of underlying mechanisms is insufficient. A crystallizable chain within a diblock copolymer assembly, for example, is expected to couple curvature to crystallization and thereby impact rigidity as well as preferred morphology, and yet the effects on dispersed phases have remained unclear. The hydrophobic polymer polycaprolactone (PCL) is semicrystalline in bulk (Tm = 60 °C) and is shown here to generate flexible worm micelles or rigid vesicles in water from several dozen poly(ethylene oxide)-based diblocks (PEO−PCL). Despite the fact that “worms” have a mean curvature between that of vesicles and spherical micelles, “worms” are seen only within a narrow, process-dependent wedge of morphological phase space that is deep within the vesicle phase. Fluorescence imaging shows worms are predominantly in one of two states − either entirely flexible with dynamic thermal undulations or fully rigid; only a few worms appear rigid at room temperature (T ≪ Tm), indicating suppression of crystallization by both curvature and PCL hydration. Worm rigidification, which depends on molecular weight, is also prevented by copolymerization of caprolactone with just 10% racemic lactide that otherwise has little impact on bulk crystallinity. In contrast to worms, vesicles of PEO−PCL are always rigid and typically leaky. Defects between crystallite domains induce dislocation-roughening with focal leakiness although select PEO−PCLwhich classical surfactant arguments would predict make wormsyield vesicles that retain encapsulant and appear smooth, suggesting a gel or glassy state. Hydration in dispersion thus tends to selectively soften high curvature microphases

Curvature-Coupled Hydration of Semicrystalline Polymer Amphiphiles Yields flexible Worm Micelles but Favors Rigid Vesicles: Polycaprolactone-Based Block Copolymers

Crystallization processes are in general sensitive to detailed conditions, but the present understanding of underlying mechanisms is insufficient. A crystallizable chain within a diblock copolymer assembly, for example, is expected to couple curvature to crystallization and thereby impact rigidity as well as preferred morphology, and yet the effects on dispersed phases have remained unclear. The hydrophobic polymer polycaprolactone (PCL) is semicrystalline in bulk (Tm = 60 °C) and is shown here to generate flexible worm micelles or rigid vesicles in water from several dozen poly(ethylene oxide)-based diblocks (PEO−PCL). Despite the fact that “worms” have a mean curvature between that of vesicles and spherical micelles, “worms” are seen only within a narrow, process-dependent wedge of morphological phase space that is deep within the vesicle phase. Fluorescence imaging shows worms are predominantly in one of two states − either entirely flexible with dynamic thermal undulations or fully rigid; only a few worms appear rigid at room temperature (T ≪ Tm), indicating suppression of crystallization by both curvature and PCL hydration. Worm rigidification, which depends on molecular weight, is also prevented by copolymerization of caprolactone with just 10% racemic lactide that otherwise has little impact on bulk crystallinity. In contrast to worms, vesicles of PEO−PCL are always rigid and typically leaky. Defects between crystallite domains induce dislocation-roughening with focal leakiness although select PEO−PCLwhich classical surfactant arguments would predict make wormsyield vesicles that retain encapsulant and appear smooth, suggesting a gel or glassy state. Hydration in dispersion thus tends to selectively soften high curvature microphases

Curvature-Coupled Hydration of Semicrystalline Polymer Amphiphiles Yields flexible Worm Micelles but Favors Rigid Vesicles: Polycaprolactone-Based Block Copolymers

Crystallization processes are in general sensitive to detailed conditions, but the present understanding of underlying mechanisms is insufficient. A crystallizable chain within a diblock copolymer assembly, for example, is expected to couple curvature to crystallization and thereby impact rigidity as well as preferred morphology, and yet the effects on dispersed phases have remained unclear. The hydrophobic polymer polycaprolactone (PCL) is semicrystalline in bulk (Tm = 60 °C) and is shown here to generate flexible worm micelles or rigid vesicles in water from several dozen poly(ethylene oxide)-based diblocks (PEO−PCL). Despite the fact that “worms” have a mean curvature between that of vesicles and spherical micelles, “worms” are seen only within a narrow, process-dependent wedge of morphological phase space that is deep within the vesicle phase. Fluorescence imaging shows worms are predominantly in one of two states − either entirely flexible with dynamic thermal undulations or fully rigid; only a few worms appear rigid at room temperature (T ≪ Tm), indicating suppression of crystallization by both curvature and PCL hydration. Worm rigidification, which depends on molecular weight, is also prevented by copolymerization of caprolactone with just 10% racemic lactide that otherwise has little impact on bulk crystallinity. In contrast to worms, vesicles of PEO−PCL are always rigid and typically leaky. Defects between crystallite domains induce dislocation-roughening with focal leakiness although select PEO−PCLwhich classical surfactant arguments would predict make wormsyield vesicles that retain encapsulant and appear smooth, suggesting a gel or glassy state. Hydration in dispersion thus tends to selectively soften high curvature microphases

Curvature-Coupled Hydration of Semicrystalline Polymer Amphiphiles Yields flexible Worm Micelles but Favors Rigid Vesicles: Polycaprolactone-Based Block Copolymers

Crystallization processes are in general sensitive to detailed conditions, but the present understanding of underlying mechanisms is insufficient. A crystallizable chain within a diblock copolymer assembly, for example, is expected to couple curvature to crystallization and thereby impact rigidity as well as preferred morphology, and yet the effects on dispersed phases have remained unclear. The hydrophobic polymer polycaprolactone (PCL) is semicrystalline in bulk (Tm = 60 °C) and is shown here to generate flexible worm micelles or rigid vesicles in water from several dozen poly(ethylene oxide)-based diblocks (PEO−PCL). Despite the fact that “worms” have a mean curvature between that of vesicles and spherical micelles, “worms” are seen only within a narrow, process-dependent wedge of morphological phase space that is deep within the vesicle phase. Fluorescence imaging shows worms are predominantly in one of two states − either entirely flexible with dynamic thermal undulations or fully rigid; only a few worms appear rigid at room temperature (T ≪ Tm), indicating suppression of crystallization by both curvature and PCL hydration. Worm rigidification, which depends on molecular weight, is also prevented by copolymerization of caprolactone with just 10% racemic lactide that otherwise has little impact on bulk crystallinity. In contrast to worms, vesicles of PEO−PCL are always rigid and typically leaky. Defects between crystallite domains induce dislocation-roughening with focal leakiness although select PEO−PCLwhich classical surfactant arguments would predict make wormsyield vesicles that retain encapsulant and appear smooth, suggesting a gel or glassy state. Hydration in dispersion thus tends to selectively soften high curvature microphases

Endothelial Targeting of Antibody-Decorated Polymeric Filomicelles

The endothelial lining of the lumen of blood vessels is a key therapeutic target for many human diseases. Polymeric filomicelles that self-assemble from polyethylene oxide (PEO)-based diblock copolymers are long and flexible rather than small or rigid, can be loaded with drugs, andmost importantlythey circulate for a prolonged period of time in the bloodstream due in part to flow alignment. Filomicelles seem promising for targeted drug delivery to endothelial cells because they can in principle adhere strongly, length-wise to specific cell surface determinants. In order to achieve such a goal of vascular drug delivery, two fundamental questions needed to be addressed: (i) whether these supramolecular filomicelles retain structural integrity and dynamic flexibility after attachment of targeting molecules such as antibodies, and (ii) whether the avidity of antibody-carrying filomicelles is sufficient to anchor the carrier to the endothelial surface despite the effects of flow that oppose adhesive interactions. Here we make targeted filomicelles that bear antibodies which recognize distinct endothelial surface molecules. We characterize these antibody targeted filomicelles and prove that (i) they retain structural integrity and dynamic flexibility and (ii) they adhere to endothelium with high specificity both in vitro and in vivo. These results provide the basis for a new drug delivery approach employing antibody-targeted filomicelles that circulate for a prolonged time yet bind to endothelial cells in vascular beds expressing select markers

Endothelial Targeting of Antibody-Decorated Polymeric Filomicelles

The endothelial lining of the lumen of blood vessels is a key therapeutic target for many human diseases. Polymeric filomicelles that self-assemble from polyethylene oxide (PEO)-based diblock copolymers are long and flexible rather than small or rigid, can be loaded with drugs, andmost importantlythey circulate for a prolonged period of time in the bloodstream due in part to flow alignment. Filomicelles seem promising for targeted drug delivery to endothelial cells because they can in principle adhere strongly, length-wise to specific cell surface determinants. In order to achieve such a goal of vascular drug delivery, two fundamental questions needed to be addressed: (i) whether these supramolecular filomicelles retain structural integrity and dynamic flexibility after attachment of targeting molecules such as antibodies, and (ii) whether the avidity of antibody-carrying filomicelles is sufficient to anchor the carrier to the endothelial surface despite the effects of flow that oppose adhesive interactions. Here we make targeted filomicelles that bear antibodies which recognize distinct endothelial surface molecules. We characterize these antibody targeted filomicelles and prove that (i) they retain structural integrity and dynamic flexibility and (ii) they adhere to endothelium with high specificity both in vitro and in vivo. These results provide the basis for a new drug delivery approach employing antibody-targeted filomicelles that circulate for a prolonged time yet bind to endothelial cells in vascular beds expressing select markers