Indoor boundary layer chemistry modeling

Ozone (O₃) chemistry is thought to dominate the oxidation of indoor surfaces. We consider the hypothesis that reactions taking place within indoor boundary layers result in greater than anticipated hydroxyl radical (OH) deposition rates. We develop models that account for boundary layer mass‐transfer phenomena, O₃‐terpene chemistry and OH formation, removal, and deposition; we solve these analytically and by applying numerical methods. For an O₃‐limonene system, we find that OH flux to a surface with an O₃ reaction probability of 10^?8 is 4.3 × 10^?5 molec/(cm² s) which is about 10 times greater than predicted by a traditional boundary layer theory. At very low air exchange rates the OH surface flux can be as much as 10% of that for O₃. This effect becomes less pronounced for more O₃‐reactive surfaces. Turbulence intensity does not strongly influence the OH concentration gradient except for surfaces with an O₃ reaction probability >10^?4. Although the O₃ flux dominates OH flux under most conditions, OH flux can be responsible for as much as 10% of total oxidant uptake to otherwise low‐reactivity surfaces. Further, OH chemistry differs from that for ozone; therefore, its deposition is important in understanding the chemical evolution of some indoor surfaces and surface films.     

Simplified Monopalmitoyl Toll-like Receptor 2 Ligand Mini-UPam for Self-Adjuvanting Neoantigen-Based Synthetic Cancer Vaccines

Synthetic vaccines, based on antigenic peptides that comprise MHC−I and MHC-II T-cell epitopes expressed by tumors, show great promise for the immunotherapy of cancer. For optimal immunogenicity, the synthetic peptides (SPs) should be adjuvanted with suitable immunostimulatory additives. Previously, we have shown that improved immunogenicity in vivo is obtained with vaccine modalities in which an SP is covalently connected to an adjuvanting moiety, typically a ligand to Toll-like receptor 2 (TLR2). SPs were covalently attached to UPam, which is a derivative of the classic TLR2 ligand Pam₃CysSK₄. A disadvantage of the triply palmitoylated UPam is its high lipophilicity, which precludes universal adoption of this adjuvant for covalent modification of various antigenic peptides as it renders the synthetic vaccine insoluble in several cases. Here, we report a novel conjugatable TLR2 ligand, mini-UPam, which contains only one palmitoyl chain, rather than three, and therefore has less impact on the solubility and other physicochemical properties of a synthetic peptide. In this study, we used SPs that contain the clinically relevant neoepitopes identified in a melanoma patient who completely recovered after T-cell therapy. Homogeneous mini-UPam-SP conjugates have been prepared in good yields by stepwise solid-phase synthesis that employed a mini-UPam building block pre-prepared in solution and the standard set of Fmoc-amino acids. The immunogenicity of the novel mini-UPam-SP conjugates was demonstrated by using the cancer patient's T-cells.     

Full scale fire tests for ship accommodation quarters

Ten full-scale test fires were conducted in a chamber simulating a three person ship accommodation quarter. The test fires used three different ventilation conditions, two types of bunks and furnishings with either polyurethane foam or chloroprene foam. The chamber was instrumented to follow the development of the fire.The furnishings with polyurethane foam were readily ignited and produced an intense fire within 2 to 4 minutes. The furnishings with chloroprene foam ignited but burned slowly with a small flame or in smoldering combustion.The ventilation conditions had a significant effect on the development and intensity of the fire as the test fires were burning under oxygen-limiting conditions.The solid pan bunks retarded the early development of the fire compared to open bunks for polyurethane furnishings. However, once the mattresses on the three bunks were ignited the intensity of the test fires was similar for both types of bunks.     

The fate of fenitrothion in a stream environment and its effect on the fauna,following aerial spraying of a Scottish forest

In order to control an infestation of Pine Beauty moth (Panolis flammea Schiff.) fenitrothion was applied at a rate of 300 g ha^?1 to a forest plantation consisting primarily of Lodgepole Pine (Pinus contorta Loud.) and Sitka Spruce (Picea sitchensis Carriere) using the ultra-low volume spraying technique. The concentration of fenitrothion in the forest stream rose to a maximum of 18μgl^?1 within the treated area an hour after spraying, but fell to 0.5 μgl^?1 after 24 hs. There was no evidence that the resident fish population was disturbed by the treatment and no short term effects were noticeable in caged fish. The concentration—time profile in the fish followed closely the profile in the water, and in each of the four fish tissues studied fell to 0.02 mg kg^?1 after 24 hs. Invertebrate drift increased markedly 12–16 hs after spraying, but decreased to around pretreatment levels within 48 hs. Caged insects remained alive during the five-day post-spray observation period, suggesting that drifting insects were displaced rather than killed by the insecticide. Concentration of fenitrothion in Willow Moss (Fontinalis antipyretica) fell from 0.139 mg kg^?1 to 0.003 mg kg^?1 (wet weight) after 48 hs. Fenitrothion was not detected in sediment but his was possibly due to the low surface area/weight ratio of the particles.     

Mapping of background air pollution at a fine spatial scale across the European Union

Background

There is a need to understand much more about the geographic variation of air pollutants. This requires the ability to extrapolate from monitoring stations to unsampled locations. The aim was to assess methods to develop accurate and high resolution maps of background air pollution across the EU.

Methods

We compared the validity of ordinary kriging, universal kriging and regression mapping in developing EU-wide maps of air pollution on a 1 × 1 km resolution. Predictions were made for the year 2001 for nitrogen dioxide (NO₂), fine particles < 10 µm (PM₁₀), ozone (O₃), sulphur dioxide (SO₂) and carbon monoxide (CO) using routine monitoring data in Airbase. Predictor variables from EU-wide databases were land use, road traffic, population density, meteorology, altitude, topography and distance to sea. Models were developed for the global, rural and urban scale separately. The best method to model concentrations was selected on the basis of predefined performance measures (R², Root Mean Square Error (RMSE)).

Results

For NO₂, PM₁₀ and O₃ universal kriging performed better than regression mapping and ordinary kriging. Validation of the final universal kriging estimates with results from all validation sites gave R²-values and RMSE-values of 0.61 and 6.73 µg/m³ for NO₂; 0.45 and 5.19 µg/m³ for PM₁₀; and 0.70 and 7.69 µg/m³ for O₃. For SO₂ and CO none of the three methods was able to provide a satisfactory prediction.

Conclusion

Reasonable prediction models were developed for NO₂, PM₁₀ and O₃ on an EU-wide scale. Our study illustrates that it is possible to develop detailed maps of background air pollution using EU-wide databases.     

Effect of seawater constituents on the performance of thermal spray aluminum in marine environments

Thermally sprayed coatings are often used to mitigate corrosion of offshore structures. They act as a physical barrier to the aggressive marine environment and as a sacrificial distributed anode for low carbon steel. In such environments, the severity of material degradation depends on many factors. The effect of temperature, exposure time or the presence of micro‐organisms are the focus of many studies, for example, however, the effect of the different ions present in seawater remains largely unexplored. The chemical composition of the water changes considerably depending on the location; industrial, glacial, estuarine, and so forth. In addition, when thermal spray aluminum (TSA) protects steel in seawater, calcareous matter precipitates as a result of the cathodic polarization and subsequent localized increase in pH. Therefore, understanding how ions such as magnesium (II), calcium (II), or carbonates alter the coating properties in the marine environment is important. This paper reports the experimental work carried out with TSA‐coated steel samples with defects to simulate mechanical damage or erosion of the coating. The combination of electrochemical tests and surface characterization provided evidence of the efficiency of the calcareous bilayer that forms on top of steel reducing the TSA degradation.     

Identification of Phenylpyrazolone Dimers as a New Class of Anti-Trypanosoma cruzi Agents

Chagas disease is becoming a worldwide problem; it is currently estimated that over six million people are infected. The two drugs in current use, benznidazole and nifurtimox, require long treatment regimens, show limited efficacy in the chronic phase of infection, and are known to cause adverse effects. Phenotypic screening of an in-house library led to the identification of 2,2′-methylenebis(5-(4-bromophenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one), a phenyldihydropyrazolone dimer, which shows an in vitro pIC₅₀ value of 5.4 against Trypanosoma cruzi. Initial optimization was done by varying substituents of the phenyl ring, after which attempts were made to replace the phenyl ring. Finally, the linker between the dimer units was varied, ultimately leading to 2,2′-methylenebis(5-(3-bromo-4-methoxyphenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one (NPD-0228) as the most potent analogue. NPD-0228 has an in vitro pIC₅₀ value of 6.4 against intracellular amastigotes of T. cruzi and no apparent toxicity against the human MRC-5 cell line and murine cardiac cells.     

An Artificial Nocturnal Flower via Humidity‐Gated Photoactuation in Liquid Crystal Networks

Beyond their colorful appearances and versatile geometries, flowers can self‐shape‐morph by adapting to environmental changes. Such responses are often regulated by a delicate interplay between different stimuli such as temperature, light, and humidity, giving rise to the beauty and complexity of the plant kingdom. Nature inspires scientists to realize artificial systems that mimic their natural counterparts in function, flexibility, and adaptation. Yet, many of the artificial systems demonstrated to date fail to mimic the adaptive functions, due to the lack of multi‐responsivity and sophisticated control over deformation directionality. Herein, a new class of liquid‐crystal‐network (LCN) photoactuators whose response is controlled by delicate interplay between light and humidity is presented. Using a novel deformation mechanism in LCNs, humidity‐gated photoactuation, an artificial nocturnal flower is devised that is closed under daylight conditions when the humidity level is low and/or the light level is high, while it opens in the dark when the humidity level is high. The humidity‐gated photoactuators can be fueled with lower light intensities than conventional photothermal LCN actuators. This, combined with facile control over the speed, geometry, and directionality of movements, renders the “nocturnal actuator” promising for smart and adaptive bioinspired microrobotics.     

Analysis of indoor particles and gases and their evolution with natural ventilation

The air composition and reactivity from outdoor and indoor mixing field campaign was conducted to investigate the impacts of natural ventilation (ie, window opening and closing) on indoor air quality. In this study, a thermal desorption aerosol gas chromatograph (TAG) obtained measurements of indoor particle‐ and gas‐phase semi‐ and intermediately volatile organic compounds both inside and outside a single‐family test home. Together with measurements from a suite of instruments, we use TAG data to evaluate changes in indoor particles and gases at three natural ventilation periods. Positive matrix factorization was performed on TAG and adsorbent tube data to explore five distinct chemical and physical processes occurring in the indoor environment. Outdoor‐to‐indoor transport is observed for sulfate, isoprene epoxydiols, polycyclic aromatic hydrocarbons, and heavy alkanes. Dilution of indoor species is observed for volatile, non‐reactive species including methylcyclohexane and decamethylcyclopentasiloxane. Window opening drives enhanced emissions of semi‐ and intermediately volatile species including TXIB, DEET, diethyl phthalate, and carvone from indoor surfaces. Formation via enhanced oxidation was observed for nonanal and 2‐decanone when outdoor oxidants entered the home. Finally, oxidative depletion of gas‐phase terpenes (eg, limonene and α‐pinene) was anticipated but not observed due to limited measurement resolution and dynamically changing conditions.