UV-chlorine advanced oxidation for potable water reuse: A review of the current state of the art and research needs.

This paper reports conclusions from a recent study completed for the Water Research Foundation and the State of California to offer guidance on UV-chlorine advanced oxidation for potable water reuse. The fundamentals of UV-chlorine advanced oxidation are discussed, and lessons learned from some of the early adopters of this technology are presented. Important highlights include the significant impact of ammonia and chloramines on UV-chlorine treatment, challenges associated with predicting UV-chlorine performance due to complex photochemistry, and an ongoing need to monitor potential byproducts and transformation products when employing any form of advanced oxidation for potable reuse.

Aerodynamic implications of gull's drooped wing-tips.

When in gliding flight, gulls are observed to adopt a drooped wing-tip configuration. This paper investigates whether this configuration might represent an aerodynamic optimum or if it is the result of constraints imposed by the gull's anatomy. A computational model was developed for the aerodynamic performance of a gull in gliding flight. This model was used in conjunction with both global and local optimizers to determine the most aerodynamically optimal configuration for cases where the gull was constrained to move its wing within its natural flapping cycle as well as when the wing had full freedom of motion. The results of this analysis determined the best wing configuration for a gull in gliding flight and demonstrated that such a configuration not only had the highest lift-to-drag ratio but also could be achieved within the constraints of the kinematics of the gull wing. These results are of interest outside studies of gulls, since the drooped wing-tip configuration could be relevant for new designs of small air vehicles.

Hemagglutinin stalk-based universal vaccine constructs protect against group 2 influenza A viruses.

Current influenza virus vaccines contain H1N1 (phylogenetic group 1 hemagglutinin), H3N2 (phylogenetic group 2 hemagglutinin), and influenza B virus components. These vaccines induce good protection against closely matched strains by predominantly eliciting antibodies against the membrane distal globular head domain of their respective viral hemagglutinins. This domain, however, undergoes rapid antigenic drift, allowing the virus to escape neutralizing antibody responses. The membrane proximal stalk domain of the hemagglutinin is much more conserved compared to the head domain. In recent years, a growing collection of antibodies that neutralize a broad range of influenza virus strains and subtypes by binding to this domain has been isolated. Here, we demonstrate that a vaccination strategy based on the stalk domain of the H3 hemagglutinin (group 2) induces in mice broadly neutralizing anti-stalk antibodies that are highly cross-reactive to heterologous H3, H10, H14, H15, and H7 (derived from the novel Chinese H7N9 virus) hemagglutinins. Furthermore, we demonstrate that these antibodies confer broad protection against influenza viruses expressing various group 2 hemagglutinins, including an H7 subtype. Through passive transfer experiments, we show that the protection is mediated mainly by neutralizing antibodies against the stalk domain. Our data suggest that, in mice, a vaccine strategy based on the hemagglutinin stalk domain can protect against viruses expressing divergent group 2 hemagglutinins.

Quantitative determination of oxalate and other organic acids in drinking water at low microgram/1 concentrations.

In this research, a recently developed ion chromatography method for organic acids was expanded to include oxalate. A major challenge was that oxalate elutes between inorganic anions such as sulfate, phosphate, bromide and nitrate, which are often present in much higher concentrations than oxalate. Optimization of the previously reported method made it possible to determine oxalate in these matrices. However, for those samples in which higher inorganic anion concentrations caused the oxalate peak to be obscured, a "heart-cut" column switching technique was used as an alternative. The method detection limit for oxalate was 9 micrograms/l with the direct approach and 6 micrograms/l for the "heat-cut" technique. These modifications represent a valuable supplement to a recently developed method for monitoring ozonation by-products in drinking water.

Determination of short-chain aliphatic, oxo- and hydroxy-acids in drinking water at low microgram per liter concentrations.

A fast and reliable ion chromatography method has been developed and applied to study the formation and consumption of organic acid ozonation by-products in a drinking water treatment plant. Water samples are injected directly into the ion chromatograph using a large sample loop (740 mu l) without any sample preparation step other than possibly filtration. Organic and inorganic anions are determined by separation on a high-capacity anion-exchange column followed by conductivity detection. The average recovery for the organic acids investigated (beta-hydroxybutyric, acetic, glycolic, butyric, formic, alpha-ketobutyric and pyruvic acid) ranged from 96 to 105%, and their method detection limits ranged from 1 to 5 mu g/l. When applied to samples taken from a drinking water treatment plant, the method proved to be reliable.

Verification of Intoximeter 3000 breath alcohol concentration by magnesium perchlorate tube method in long-term field program.

The anhydrous magnesium perchlorate (MPT) breath alcohol sample collection tube was analyzed by gas chromatography (GC) to verify paired breath alcohol concentrations obtained from 18 Intoximeter 3000 (IR) instruments under normal conditions of use. This study compares the accuracy, precision, and reliability of actual driving-while-intoxicated (DWI) IR breath alcohol evidence gathered by field law enforcement personnel with the GC results of the MPT alcohol analysis. The IR and MPT-GC breath alcohol concentration results from a total of 1024 individuals were determined. Results of 530 (51.7%) MPT-GC breath alcohol analyses deviated within +/- 0.010 g/210 L from their paired IR breath alcohol result; 817 (79.7%) and 945 (92.3%) MPT-GC breath alcohol analyses deviated within +/- 0.020 and +/- 0.030 g/210 L, respectively. Confidence interval limits at various probability levels are tabulated and show expected reliability of a single predicted IR breath alcohol concentration from the IR on MPT-GC linear regression analysis.