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We describe studies undertaken in support of the Far-infrared Outgoing Radiation Understanding and Monitoring (FORUM) mission, ESA’s ninth Earth Explorer, designed to investigate whether airborne observations of far-infrared radiances can provide beneficial information on mid and upper tropospheric water vapour concentrations.Initially we perform a joint temperature and water vapour retrieval and show that the water vapour retrieval exploiting far-infrared measurements from the Tropospheric Airborne Fourier Transform Spectrometer (TAFTS) shows improvement over the a-priori Unified Model global forecast when compared to in situ dropsonde measurements. For this case the improvement is particularly noticeable in the mid-upper troposphere. Equivalent retrievals using mid-infrared radiances measured by the Airborne Research Interferometer Evaluation System (ARIES) show much reduced performance, with the degrees of freedom for signal (DFS), reduced by a factor of almost 2. Further sensitivity studies show that this advantage is decreased, but still present when the spectral resolution of the TAFTS measurements is reduced to match that of ARIES.The beneficial role of the far infrared for this case is further confirmed by performing water vapour only retrievals using ARIES and TAFTS individually, and then in combination. We find that the combined retrieval has a DFS value of 6.7 for water vapour, marginally larger than that obtained for the TAFTS retrieval and almost twice as large as that obtained for ARIES.These results provide observational support of theoretical studies highlighting the potential improvement that far-infrared observations could bring for the retrieval of tropospheric water vapour.

Global environmental change is one of the most pressing issues facing future generations. Equipping schoolchildren with a clear understanding of physical geography is therefore a key educational priority. Effectively engaging schoolchildren with complex scientific ideas can be challenging, but with the appropriate tools, scientists can play a valuable role in developing meaningful science communication experiences. Climate Explorers addressed these issues by forging a collaboration between physical geography and social science academics, and 320 UK school students and their teachers in seven primary (elementary) schools. Using insights from co-production techniques and storytelling, the project aimed to 1) produce new open access, online climate science education resources, and 2) test co-production and storytelling approaches to physical geography science engagement. Our findings demonstrated that school children responded especially well to working with ‘real life’ scientists, where meaningful and memorable educational interactions were forged through the use of narratives, personal experiences and tailored language. Here we summarise our approach, and provide templates that can be readily applied by scientists working across the physical geography spectrum anywhere in the world. The flexibility of the templates means that they can be adapted and developed for a range of formats, from small-scale community workshops to national-scale educational initiatives, for delivery both in-person or online. We hope that our approach will provide a springboard to transform and enhance physical geography science communication more broadly.

The INCOMPASS field campaign combines airborne and ground measurements of the 2016 Indian monsoon, towards the ultimate goal of better predicting monsoon rainfall. The monsoon supplies the majority of water in South Asia, but forecasting from days to the season ahead is limited by large, rapidly developing errors in model parametrizations. The lack of detailed observations prevents thorough understanding of the monsoon circulation and its interaction with the land surface: a process governed by boundary- layer and convective-cloud dynamics. INCOMPASS used the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft for the first project of this scale in India, to accrue almost 100 h of observations in June and July 2016. Flights from Lucknow in the northern plains sampled the dramatic contrast in surface and boundary-layer structures between dry desert air in the west and the humid environment over the northern Bay of Bengal. These flights were repeated in pre-monsoon and monsoon conditions. Flights from a second base at Bengaluru in southern India measured atmospheric contrasts from the Arabian Sea, over the Western Ghats mountains, to the rain shadow of southeast India and the south Bay of Bengal. Flight planning was aided by forecasts from bespoke 4 km convection-permitting limited-area models at the Met Office and India's NCMRWF. On the ground, INCOMPASS installed eddy- covariance flux towers on a range of surface types, to provide detailed measurements of surface fluxes and their modulation by diurnal and seasonal cycles. These data will be used to better quantify the impacts of the atmosphere on the land surface, and vice versa. INCOMPASS also installed ground instrumentation supersites at Kanpur and Bhubaneswar. Here we motivate and describe the INCOMPASS field campaign. We use examples from two flights to illustrate contrasts in atmospheric structure, in particular the retreating mid-level dry intrusion during the monsoon onset.

Desert dust is one of the most important atmospheric ice‐nucleating aerosol species around the globe. However, there have been very few measurements of ice‐nucleating particle (INP) concentrations in dusty air close to desert sources. In this study we report the concentration of INPs in dust laden air over the tropical Atlantic within a few days' transport of one of the world's most important atmospheric sources of desert dust, the Sahara. These measurements were performed as part of the Ice in Clouds Experiment‐Dust campaign based in Cape Verde, during August 2015. INP concentrations active in the immersion mode, determined using a droplet‐on‐filter technique, ranged from around 102 m−3 at −12°C to around 105 m−3 at −23°C. There is about 2 orders of magnitude variability in INP concentration for a particular temperature, which is determined largely by the variability in atmospheric dust loading. These measurements were made at altitudes from 30 to 3,500 m in air containing a range of dust loadings. The ice active site density (ns) for desert dust dominated aerosol derived from our measurements agrees with several laboratory‐based parameterizations for ice nucleation by desert dust within 1 to 2 orders of magnitude. The small variability in ns values determined from our measurements (within about 1 order of magnitude) is striking given that the back trajectory analysis suggests that the sources of dust were geographically diverse. This is consistent with previous work, which indicates that desert dust's ice‐nucleating activity is only weakly dependent on source.

Background: There is an increased prevalence of diabetes. Doctors in training, irrespective of specialty, will have patients with diabetes under their care.\ud \ud Aim: To determine levels of confidence of doctors in training in the management of diabetes and establish their training needs in this area of clinical practice.\ud \ud Design: A national online survey of trainee doctors in the UK using a pre-validated questionnaire.\ud \ud Methods: A four-point confidence rating scale was used to rate confidence in the management of diabetes and comparators. A six-point scale was used to quantify how often trainees would contribute to the management of patients with diabetes and trainees were asked about their training in managing diabetes.\ud \ud Results: A total of 2149 doctors completed the survey. The percentage ‘fully confident’ in diagnosing diabetes was 27%, diagnosing and managing hypoglycaemia 55%, diagnosing and managing diabetic ketoacidosis 43%, managing intravenous (IV) insulin 27%, prescribing IV fluids for patients with diabetes 39% and altering diabetes therapy prior to surgery/other procedure 18%. In comparison, 66% and 65% were ‘fully confident’ in the management of angina and asthma, respectively (P 80% of the time. Respectively, 19% and 35% of respondents reported that their undergraduate and postgraduate training had prepared them adequately to optimize treatment of diabetes. The majority (>70%) wanted further training in managing all aspects of diabetes care.\ud \ud Conclusions: Trainee doctors in the UK lack confidence in the management of diabetes, are unlikely to take the initiative to optimize glycaemic control and report a need for further training.

Secondary organic material (SOM) constitutes a large mass fraction of atmospheric aerosol particles. Understanding its impact on climate and air quality relies on accurate models of interactions with water vapour. Recent research shows that SOM can be highly viscous and can even behave mechanically like a solid, leading to suggestions that particles exist out of equilibrium with water vapour in the atmosphere. In order to quantify any kinetic limitation we need to know water diffusion coefficients for SOM, but this quantity has, until now, only been estimated and has not yet been measured. We have directly measured water diffusion coefficients in the water soluble fraction of α-pinene SOM between 240 and 280 K. Here we show that, although this material can behave mechanically like a solid, at 280 K water diffusion is not kinetically limited on timescales of 1 s for atmospheric-sized particles. However, diffusion slows as temperature decreases. We use our measured data to constrain a Vignes-type parameterisation, which we extend to lower temperatures to show that SOM can take hours to equilibrate with water vapour under very cold conditions. Our modelling for 100 nm particles predicts that under mid- to upper-tropospheric conditions radial inhomogeneities in water content produce a low viscosity surface region and more solid interior, with implications for heterogeneous chemistry and ice nucleation.

Most studies of the role of biological entities as atmospheric ice-nucleating particles have focused on relatively rare supermicron particles such as bacterial cells, fungal spores and pollen grains. However, it is not clear that there are sufficient numbers of these particles in the atmosphere to strongly influence clouds. Here we show that the ice-nucleating activity of a fungus from the ubiquitous genus Fusarium is related to the presence of nanometre-scale particles which are far more numerous and therefore potentially far more important for cloud glaciation than whole intact spores or hyphae. In addition, we quantify the ice-nucleating activity of nano-ice nucleating particles (nano-INPs) washed off pollen and also show that nano-INPs are present in a soil sample. Based on these results, we suggest that there is a reservoir of biological nano-INPs present in the environment which may, for example, become aerosolised in association with fertile soil dust particles.

Indium is widely used in the semiconductor and microelectronics industries often in particulate form with examples being indium phosphide (InP) and indium-tin oxide (ITO). ITO, which typically consists of approximately 90% indium oxide (In2O3) and 10% tin oxide (SnO2) by weight, is used in the manufacture of flat panel displays (Guo et al., 2011) and accounts for a large percentage of the total indium demand in Japan (Tanaka et al., 2010). ITO can be sintered or non-sintered; although the sintered form is most commonly used for industrial applications. Concerns have been raised over the safety and health of industry workers exposed to particulate aerosols when working with materials containing these compounds. Inhalation exposure to indium-containing particles (ICPs) within an occupational setting, mostly ITO, has been associated with increased concentrations of indium measured in the blood, serum, and urine of workers and in the development of interstitial lung disease (Chonan et al., 2007; Hamaguchi et al., 2008; Homma et al., 2005; Liu et al., 2012; Miyaki et al., 2003; Nakano et al., 2009) as well as pulmonary alveolar proteinosis (Cummings et al., 2010; Xiao et al., 2010). In fact, inhalation exposure to ITO in an occupational setting has resulted in two fatalities (Cummings et al., 2010; Homma et al., 2003). The American Conference of Governmental Industrial Hygienists (ACGIH) has recommended an occupational exposure limit of 0.1 mg/m3 (threshold limit value-time weighted average) for all indium compounds (ACGIH, 2007). A critical issue to be addressed is whether the toxicity of ICPs can be predicted based on the total amount of indium present in the compound, the other constituents (eg, tin in ITO), and/or the solubilization potential. Indium ions released from the parent compound by solubilization are likely the main toxic constituents of some ICPs. Subchronic and chronic inhalation exposure of rats and mice to InP and ITO particles resulted in pulmonary toxicity including severe alveolar proteinosis, chronic inflammation, interstitial fibrosis, and alveolar epithelial hyperplasia/metaplasia (Gottschling et al., 2001; Nagano et al., 2011a,b,c; NTP, 2001). In addition, carcinogenicity was observed after chronic inhalation exposure to InP and ITO in rodents and included increased incidences of alveolar/bronchiolar adenomas and carcinomas as well as squamous cell carcinoma of the lung (Gottschling et al., 2001; Nagano et al., 2011c; NTP, 2001). Administration of InP or ITO particles via oropharnygeal aspiration (Kirby et al., 2009; Lison et al., 2009) or intratracheal instillation (Tanaka et al., 2002, 2010; Yamazaki et al., 2000) also induced pulmonary injury, inflammation, and pleural effects. Upon deposition within the lung, alveolar macrophages (AMs) and likely epithelial cells initially phagocytoze the InP and ITO particles which are insoluble at physiological pH; however, the mechanism(s) responsible for pulmonary toxicity is unclear. We recently showed in vitro that uptake of InP and ITO by macrophages (RAW 264.7 cells) and solubilization through the phagolysosomal acidification pathway after 24 h of treatment resulted in particle-induced cytotoxicity and the extracellular release of ionic indium (Gwinn et al., 2013), presumably the primary cytotoxic constituent of InP and ITO. In this previous study, we developed a cell-based assay using graphite furnace-atomic absorption spectroscopy (GF-AAS) to measure the solubilization of ICPs and release of “free” ionic indium by macrophages. Lung epithelial (LA-4) cells were also shown to phagocytoze InP and ITO; however, unlike macrophages, these cells did not solubilize the particles and were resistant to particle-induced cytotoxicity after 24 h of treatment (Gwinn et al., 2013). The InP and ITO used in this previous study were of very different particle diameters and thus a valid direct comparison proved problematic with regards to relative particle solubilization and cytotoxicity. In the current study, we compared the macrophage solubilization (release of ionic indium) and cytotoxicity of InP and ITO with similar particle diameters (∼1.5 µm) and then determined if relative differences in these in vitro parameters correlated with pulmonary toxicity in vivo. Our results showed that macrophage cytotoxicity and release of ionic indium in vitro as well as pulmonary toxicity in vivo were much greater for InP compared with ITO. This suggests that macrophage solubilization and particle-induced cytotoxicity of some ICPs in vitro are capable of predicting pulmonary toxicity in vivo. Furthermore, these differences in particle toxicity were observed despite the two compounds having similar indium content suggesting that particle solubilization, not total indium content, better reflects the toxic potential of some ICPs. Finally, we also demonstrated that soluble InCl3 containing equivalent amounts of indium to that of insoluble particulate InP was more cytotoxic than InP to macrophages and lung epithelial cells in vitro suggesting that ionic indium is the primary cytotoxic constituent of InP.

Recent research suggests that under certain temperature and relative humidity conditions atmospheric aerosol may be present in the form of a glassy solid. In order to understand the impacts that this may have on aerosol–cloud interactions and atmospheric chemistry, knowledge of water diffusion within such aerosol particles is required. Here, a method is described in which Raman spectroscopy is used to observe D2O diffusion in high-viscosity aqueous solutions, enabling a quantitative assessment of water diffusion coefficients, Dwater, as a function of relative humidity. Results for sucrose solutions compare well with literature data at 23.5 ± 0.3 °C, and demonstrate that water diffusion is slow (Dwater ~5 × 10−17 m2 s−1), but not arrested, just below the glass transition at a water activity of 0.2. Room temperature water diffusion coefficients are also presented for aqueous levoglucosan and an aqueous mixture of raffinose, dicarboxylic acids and ammonium sulphate: at low humidity, diffusion is retarded but still occurs on millisecond to second timescales in atmospherically relevant-sized particles. The effect of gel formation on diffusion in magnesium sulfate solutions is shown to be markedly different from the gradual decrease in diffusion coefficients of highly viscous liquids. We show that using the Stokes–Einstein equation to determine diffusion timescales from viscosity leads to values which are more than 5 orders of magnitude too big, which emphasises the need to make measurements of diffusion coefficients. In addition, comparison of bounce fraction data for levoglucosan with measured diffusion data reveals that even when particles bounce the diffusion timescales for water are a fraction of a second for a 100 nm particle. This suggests a high bounce fraction does not necessarily indicate retarded water diffusion.

Agricultural dust emissions have been estimated to contribute around 20% to the global dust burden. In contrast to dusts from arid source regions, the ice-nucleating abilities of which have been relatively well studied, soil dusts from fertile sources often contain a substantial fraction of organic matter. Using an experimental methodology which is sensitive to a wide range of ice nucleation efficiencies, we have characterised the immersion mode ice-nucleating activities of dusts (d < 11 μm) extracted from fertile soils collected at four locations around England. By controlling droplet sizes, which ranged in volume from 10−12 to 10−6 L (concentration = 0.02 to 0.1 wt% dust), we have been able to determine the ice nucleation behaviour of soil dust particles at temperatures ranging from 267 K (−6 °C) down to the homogeneous limit of freezing at about 237 K (−36 °C). At temperatures above 258 K (−15 °C) we find that the ice-nucleating activity of soil dusts is diminished by heat treatment or digestion with hydrogen peroxide, suggesting that a major fraction of the ice nuclei stems from biogenic components in the soil. However, below 258 K, we find that the ice active site densities tend towards those expected from the mineral components in the soils, suggesting that the inorganic fraction of soil dusts, in particular the K-feldspar fraction, becomes increasingly important in the initiation of the ice phase at lower temperatures. We conclude that dusts from agricultural activities could contribute significantly to atmospheric IN concentrations, if such dusts exhibit similar activities to those observed in the current laboratory study.

Short-term inhalation exposure of B6C3F1 mice to styrene causes necrosis of centrilobular (CL) hepatocytes. However, in spite of continued exposure, the necrotic parenchyma is rapidly regenerated, indicating resistance by regenerated cells to styrene toxicity. These studies were conducted to test the hypothesis that resistance to repeated styrene exposure is due to sustained cell proliferation, with production of hepatocytes that have reduced metabolic capacity. Male mice were exposed to air or 500 ppm styrene (6 h/day); hepatotoxicity was evaluated by microscopic examination, serum liver enzyme levels, and bromodeoxyuridine (BrdU)-labeling index (LI). Metabolism was assessed by measurement of blood styrene and styrene oxide. Both single and repeated exposures to styrene resulted in mortality by Day 2; in mice that survived, there was CL necrosis with elevated BrdU LI at Day 6, and complete restoration of the necrotic parenchyma by Day 15. The BrdU LI in mice given a single exposure had returned to control levels by Day 15. Re-exposure of these mice on Day 15 resulted in additional mortality and hepatocellular necrosis, indicating that regenerated CL cells were again susceptible to the cytolethal effect of styrene following a 14-day recovery. However, in mice repeatedly exposed to styrene for 14 days, the BrdU LI remained significantly increased on Day 15, with preferential labeling of CL hepatocytes with enlarged nuclei (karyomegaly). If repeated exposures were followed by a 10-day recovery period, CL karyomegaly persisted, but the BrdU LI returned to control level and CL hepatocytes became susceptible again to styrene toxicity as demonstrated by additional mortality and acute necrosis after a challenge exposure. These findings indicated a requirement for continued styrene exposure and DNA synthesis in order to maintain this resistant phenotype. Analyses of proliferating-cell nuclear-antigen (PCNA) labeling were conducted to further characterize the cell cycle kinetics of these hepatocytes. The proportion of cells in S-phase was increased by repeated exposure. However, PCNA analysis also revealed an even larger increase in the G1 cell compartment with repeated exposures, without a concurrent increase in G2 phase or in mitotic cell numbers. These data indicate that resistance to styrene-induced necrosis under conditions of repeated exposure is not due to sustained cell turnover and production of new, metabolically inactive cells, but rather is due to some other, as yet unknown, protective phenotype of the regenerated cells.

alpha-Methylstyrene (AMS) is a chemical intermediate used in the synthesis of specialty polymers and copolymers. Inhalation studies of AMS were conducted because of the lack of toxicity data and the structural similarity of AMS to styrene, a toxic and potentially carcinogenic chemical. Male and female B6C3F1 mice were exposed to 0, 600, 800, or 1000 ppm AMS 6 h/day, 5 days/week, for 12 days. After 1 exposure, 21% (5/24) of female mice were found dead in the 1000-ppm group, 56% (10/18) in the 800-ppm group, and 6% (1/18) in the 600-ppm concentration group. After 12 exposures, relative liver weights were significantly increased and relative spleen weights were significantly decreased in both male and female mice at all concentrations. No microscopic treatment-related lesions were observed. A decrease in hepatic glutathione (GSH) was associated with AMS exposure for 1 and 5 days. Male and female F344 rats were exposed to 0, 600 or 1000 ppm AMS for 12 days. No mortality or sedation occurred in AMS-exposed rats. Relative liver weights were significantly increased in both males and females after 12 exposures to 600 or 1000 ppm. An increased hyaline droplet accumulation was detected in male rats in both concentration groups; no significant microscopic lesions were observed in other tissues examined. Exposure of male and female F344 rats and male NBR rats to 0, 125, 250 or 500 ppm AMS, 6 h/day for 9 days resulted in increased accumulation of hyaline droplets in the renal tubules of male F344 rats in the 250 and 500 ppm concentration groups. Although AMS and styrene are structurally very similar, AMS was considerably less toxic for mice and more toxic for male rats than styrene.

Agricultural dust emissions have been estimated to contribute around 20% to the global dust burden. In contrast to dusts from arid source regions, the ice-nucleating abilities of which have been relatively well studied, soil dusts from fertile sources often contain a substantial fraction of organic matter. Using an experimental methodology which is sensitive to a wide range of ice nucleation efficiencies, we have characterised the immersion mode ice-nucleating activities of dusts extracted from fertile soils collected at four locations around England. By controlling droplet sizes, which ranged in volume from 10−12 to 10−6 L, we have been able to determine the ice nucleation behaviour of soil dust particles at temperatures ranging from 267 K (−6 °C) down to the homogeneous limit of freezing at about 237 K (−36 °C). At temperatures above 258 K (−15 °C) we find that the ice-nucleating activity of soil dusts is diminished by heat treatment or digestion with hydrogen peroxide, suggesting that the ice nuclei stem from biogenic components in the soil. However, below 258 K, we find that the ice active site densities tend towards those expected from the mineral components in the soils, suggesting that the inorganic fraction of soil dusts, in particular the K-feldspar fraction, becomes increasingly important in the initiation of the ice phase at lower temperatures. We conclude that although only a relatively minor contributor to the global atmospheric dust burden, the enhanced IN activities of dusts generated from agricultural activities may play an important role in cloud glaciation, particularly at temperatures above 258 K.

There is no generally accepted value for the lower temperature limit for life on Earth. We present empirical evidence that free-living microbial cells cooling in the presence of external ice will undergo freeze-induced desiccation and a glass transition (vitrification) at a temperature between -10 degrees C and -26 degrees C. In contrast to intracellular freezing, vitrification does not result in death and cells may survive very low temperatures once vitrified. The high internal viscosity following vitrification means that diffusion of oxygen and metabolites is slowed to such an extent that cellular metabolism ceases. The temperature range for intracellular vitrification makes this a process of fundamental ecological significance for free-living microbes. It is only where extracellular ice is not present that cells can continue to metabolise below these temperatures, and water droplets in clouds provide an important example of such a habitat. In multicellular organisms the cells are isolated from ice in the environment, and the major factor dictating how they respond to low temperature is the physical state of the extracellular fluid. Where this fluid freezes, then the cells will dehydrate and vitrify in a manner analogous to free-living microbes. Where the extracellular fluid undercools then cells can continue to metabolise, albeit slowly, to temperatures below the vitrification temperature of free-living microbes. Evidence suggests that these cells do also eventually vitrify, but at lower temperatures that may be below -50 degrees C. Since cells must return to a fluid state to resume metabolism and complete their life cycle, and ice is almost universally present in environments at sub-zero temperatures, we propose that the vitrification temperature represents a general lower thermal limit to life on Earth, though its precise value differs between unicellular (typically above -20 degrees C) and multicellular organisms (typically below -20 degrees C). Few multicellular organisms can, however, complete their life cycle at temperatures below similar to-2 degrees C.

Iodine oxide particles are known to nucleate in the marine boundary layer where gas phase molecular iodine and organoiodine species are produced by macroalgae. These ultra-fine particles may then grow through the condensation of other materials to sizes where they may serve as cloud condensation nuclei. There has been some debate over the chemical identity of the initially nucleated particles. In laboratory simulations, hygroscopic measurements have been used to infer that they are composed of insoluble I2O4, while elemental analysis of laboratory generated particles suggests soluble I2O5 or its hydrated form iodic acid, HIO3 (I2O5·H2O). In this paper we explore the response of super-micron sized aqueous iodic acid solution droplets to varying humidity using both Raman microscopy and single particle electrodynamic traps. These measurements reveal that the propensity of an iodic acid solution droplet to crystallise is negligible on drying to ~0% relative humidity (RH). On applying mechanical pressure to these droplets they shatter in a manner consistent with an ultra-viscous liquid or a brittle glass. Water retention in amorphous material at low RH is important for understanding the hygroscopic growth of aerosol particles and uptake of other condensable material. Subsequent water uptake between 10 and 20% RH causes their viscosity to reduce sufficiently that the cracked droplets flow and merge. The persistence of iodic acid solution in an amorphous state, rather than a crystalline state, suggests they will more readily accommodate other condensable material and are therefore more likely to grow to sizes where they may serve as cloud condensation nuclei. On increasing the humidity to ~90% the mass of the droplets only increases by ~20% with a corresponding increase in radius of only 6%, which is remarkably small for a highly soluble material. We suggest that the small growth factor of aqueous iodic acid solution droplets is consistent with the small aerosol growth factors observed in previous experiments.

Atmospheric secondary organic aerosol (SOA) is likely to exist in a semi-solid or glassy state, particularly at low temperatures and humidities. Previously, it has been shown that glassy aqueous citric acid aerosol is able to nucleate ice heterogeneously under conditions relevant to cirrus in the tropical tropopause layer (TTL). In this study we test if glassy aerosol distributions with a range of chemical compositions heterogeneously nucleate ice under cirrus conditions. Three single component aqueous solution aerosols (raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA) and levoglucosan) and one multi component aqueous solution aerosol (raffinose mixed with five dicarboxylic acids and ammonium sulphate) were studied in both the liquid and glassy states at a large cloud simulation chamber. The investigated organic compounds have similar functionality to oxidised organic material found in atmospheric aerosol and have estimated temperature/humidity induced glass transition thresholds that fall within the range predicted for atmospheric SOA. A small fraction of aerosol particles of all compositions were found to nucleate ice heterogeneously in the deposition mode at temperatures relevant to the TTL (ns, of the aerosols tested here and also of glassy citric acid aerosol as a function of relative humidity with respect to ice (RHi). We also propose a parameterisation which can be used to estimate heterogeneous ice nucleation by glassy aerosol for use in cirrus cloud models up to ~220 K. Finally, we show that heterogeneous nucleation by glassy aerosol may compete with ice nucleation on mineral dust particles in mid-latitudes cirrus.

Iodine oxide particles are known to nucleate in the marine boundary layer where gas phase molecular iodine and organoiodine species are produced by macroalgae. There has been some debate over the chemical identity of these particles. Hygroscopic measurements have been used to infer that they are composed of insoluble I2O4, while elemental analysis of laboratory generated particles suggests soluble I2O5 or its hydrated form iodic acid, HIO3 (I2O5 · H2O). In this paper we explore the response of super-micron sized aqueous iodic acid solution droplets to varying humidity using both Raman microscopy and single particle electrodynamic traps. These measurements reveal that the propensity of an iodic acid solution droplet to crystallise is negligible on drying to ~0% relative humidity (RH). On applying mechanical pressure to these droplets they shatter in a manner consistent with an ultra-viscous liquid or a brittle glass, but subsequent water uptake between 10 and 20% RH causes their viscosity to reduce sufficiently that the cracked droplets flow and merge. The persistence of iodic acid solution in an amorphous state, rather than a crystalline state, suggests they will more readily accommodate other condensable material and are therefore more likely to grow to sizes where they may serve as cloud condensation nuclei. On increasing the humidity to ~90% the mass of the droplets only increases by ~20% with a corresponding increase in radius of only ~6 %, which is remarkably small for a highly soluble material. We suggest that the small growth factor of aqueous iodic acid solution droplets is consistent with the small aerosol growth factors observed in field experiments.

The Young Diabetologists' Forum (YDF) is a group designed and run by specialist trainees in endocrinology and diabetes that aims to provide high quality educational events. The YDF recognised that not all trainees in the specialty had equitable access to training opportunities and resolved to try and remedy the situation. This article describes the history and evolution of the YDF into an organisation representing over 400 trainees in endocrinology and diabetes, providing up to seven training events per year and with a budget of over pounds 200,000. As well as offering education and training another key purpose of the YDF is to give trainees from around the country the opportunity to meet up and exchange thoughts and ideas. The overall aim of the organisation is to improve the lives of people with diabetes by helping to ensure that future specialists are fully equipped for their role.

The National Toxicology Program is conducting a chemical class study to investigate the structure-activity relationships for the toxicity of alpha,beta-unsaturated ketones. Ethyl vinyl ketone (EVK) was selected for study because it is a representative straight-chain aliphatic alpha,beta-unsaturated ketone with extensive use and widespread exposure. Short-term inhalation studies of EVK were conducted to provide toxicity data for comparison with the related alpha,beta-unsaturated ketones 2-cyclohexene-1-one (CHX) and methyl vinyl ketone (MVK). These data will be used in designing chronic toxicity and carcinogenicity studies of these ketones. Male and female F344 rats and B6C3F1 mice were exposed to 0, 2, 4, or 8 ppm EVK 6 h/day, 5 days/wk for 13 wk. The nasal cavity was the major target organ of EVK in both rats and mice. Pathologic findings in both the olfactory and respiratory epithelium were observed. Lesions consisted primarily of olfactory epithelial necrosis, atrophy and regeneration, and/or hyperplasia and squamous metaplasia of the respiratory epithelium. Squamous metaplasia of the respiratory epithelium was present in all rats and mice exposed to 4 and 8 ppm EVK, and these lesions were more severe in rats than in mice. Few systemic effects were observed in rats and mice exposed to EVK. A transient decrease in total leukocytes due to decrements in lymphocyte and monocyte populations was present in male rats after exposure to 8 ppm for 3 and 21 days; however, this effect was not present after exposure for 13 wk. There were no chemical-related effects on micronucleus formation in mice, or on sperm motility and vaginal cytology in either species. EVK, like other alpha,beta-unsaturated ketones, is a reactive, direct-acting gaseous irritant with toxicity limited primarily to the upper respiratory tract.

Epidemiological studies finding menstrual cycle abnormalities among women occupationally exposed to Hg degrees prompted us to investigate the mechanisms of reproductive toxicity of Hg degrees in the female rat. Nose-only Hg degrees vapor inhalation exposures were conducted on regularly cycling rats 80-90 days of age in dose-response and acute time-course studies, which have previously proven useful as a model to identify ovarian toxicants. Vaginal smears were evaluated daily and serum hormone levels were correlated with cycle and with ovarian morphology at necropsy. Exposure concentration-related effects of Hg degrees were evaluated by exposing rats to 0, 1, 2, or 4 mg/m3 Hg degrees vapor 2 h/day for 11 consecutive days. Tissue Hg levels correlated with exposure concentration and duration. Exposure of rats to 4 mg/m3 (but not 1 or 2 mg/m3) Hg vapor for 11 days resulted in significant decreases in body weights relative to controls. Estrous cycles were slightly prolonged in the 2 and 4 mg/m3 dose groups, and serum estradiol and progesterone levels were significantly different in the 4 mg/m3 group compared to controls. The alterations in cycle and hormones at the 4 mg/m3 exposure concentration were attributed to body weight loss and generalized toxicity. In the time-course study, rats were exposed to 2 mg/m3 Hg degrees or air beginning in metestrus and evaluated daily for 8 days. A lengthening of the cycle was detected and morphological changes were observed in the corpora lutea (CL) after exposure for 6 days. To determine if changes in the CL and cyclicity correlated with a functional defect, rats were exposed to Hg degrees vapor and evaluated for pregnancy outcome. There were no significant effects on pregnancy rate or numbers of implantation sites when rats were exposed to 1 or 2 mg/m3 Hg degrees for 8 days prior to breeding, or when exposed for 8 days after breeding. These studies indicate that exposure to Hg degrees vapor altered estrous cyclicity, but had no significant effect on ovulation, implantation, or maintenance of first pregnancy during exposure of short duration in female rats.

Mass spectra of the permethyl derivatives of a series of glycosphingolipids have been recorded. Fragments containing one, two and in some cases three sugar moieties were detected for the polyglycosyl compounds, several of these being of high intensity. The utility of such ions in establishing the position of hexosamine in an oligosaccharide chain was demonstrated. Low molecular weight gangliosides gave peaks corresponding to permethylated sialic acid under certain experimental conditions, permitting identification of N-acetyl- and N-glycoclylneuraminic acids. Glass sample containers appeared to catalyze destruction of these units. Peaks corresponding to the entire ceramide unit were detected but only in a few instances did these reflect the true ceramide composition. Specific fragments derived from the fatty acids and long-chain bases, respectively, were shown to be useful for qualitative identification of these components.

The 4.350 MeV(3+) and 5.716 MeV(4+) states in 26Mg have been studied with particle gamma ray angular correlation measurements using the reactions 26Mg( alpha alpha ' gamma ) 26Mg with Ge(Li) detectors. Branching ratios and E2/M1 mixing ratios were deduced; in particular a new 815 keV transition (5.716 to 4.901 MeV) has been found. The E2 transition strengths of the cascading gamma rays with 1366 keV (4+ to 3+) and 1412 keV (3+ to 2+) of 3+or-1 and 9-3+4 Weisskopf units respectively support the assignment of the 4.350 and 5.716 MeV states to the Kpi =2+ rotational band based on the 2.938 MeV (2+) states. The results are compared with recent deformed shell model calculations. Nineteen further states between 6 and 9.1 MeV were excited; a decay scheme has been established and several branching ratios are reported. The possible assignment of high spins to some of the higher states is discussed.

Several annual and perennial weed species were effectively controlled with 3-tert-butyl-5-chloro-6-methyluracil (terbacil) in orchards. One-year-old seedling rootstocks of peach, Prunus persica, (L.) Patsch, were most tolerant to terbacil; pear, Pyrus communis, L., and apple, Malus sylvestris, L., seedlings were intermediate; the East Malling (EM) VII clone, Mazzard, Prunus avium, L., and Mahaleb cherry, Prunus mahaleb, L., seedlings were most susceptible. Both surface and soil incorporated applications were toxic, indicating that terbacil was readily leached into the root zone. Applications were made in 2 and 6-year-old experimental blocks and in commercial orchards (age 2–15 years) from 1965 to 1968. No major damage was observed on apple, peach, tart cherry or sweet cherry trees that were established 3 years or longer. Toxicity symptoms manifested as veinal chlorosis were occasionally observed on sandy loam soils at rates 2–3 fold greater than required for satisfactory weed control.

We report the first direct measurements of sucrose diffusion in aqueous solution at sucrose mass fractions above 0.75., The diffusion of sugar in aqueous solution is important both in nature and in technological applications, yet measurements of diffusion coefficients at low water content are scarce. We report directly measured sucrose diffusion coefficients in aqueous solution. Our technique utilises a Raman isotope tracer method to monitor the diffusion of non-deuterated and deuterated sucrose across a boundary between the two aqueous solutions. At a water activity of 0.4 (equivalent to 90 wt% sucrose) at room temperature, the diffusion coefficient of sucrose was determined to be approximately four orders of magnitude smaller than that of water in the same material. Using literature viscosity data, we show that, although inappropriate for the prediction of water diffusion, the Stokes–Einstein equation works well for predicting sucrose diffusion under the conditions studied. As well as providing information of importance to the fundamental understanding of diffusion in binary solutions, these data have technological, pharmaceutical and medical implications, for example in cryopreservation. Moreover, in the atmosphere, slow organic diffusion may have important implications for aerosol growth, chemistry and evaporation, where processes may be limited by the inability of a molecule to diffuse between the bulk and the surface of a particle.

Pepper transplants (Capsicum annuum L.) held under simulated transit conditions synthesized substantial amounts of ethylene, the rate of which was temperature dependent. Transplants treated with known concentrations of ethylene (0, 0.1 to 10.0 μ1/liter) were substantially defoliated at levels lower than those that may be produced in transit by the plants themselves. Exposure to ethylene concentrations of 0.5 jul/liter and greater impeded the growth of transplants after planting into the field. Removal of ethylene in storage with potassium permanganate greatly reduced abscission. Elevated storage CO2 levels stimulated ethylene synthesis by as much as 34%.

A double-blind trial in two randomly structured groups of boarders (44 girls and 66 boys) aged 7 to 13 years was undertaken in two Bristrol schools. Dosage was 1 ml a day of fluid (antigen or placebo) orally for the first four weeks of the autumn term, absenteeism being the main parameter measured, using a structured recording code. There was a highly significant difference in the number of days lost from upper respiratory-tract infection in the treated as opposed to the placebo group (x2 = 40-00 P less than 0-001 (v = 1). The number of colds was also significantly lower in the treated group (x2 = 8-05 P less than 0-005 (V less than i)).

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Seed of germinated celery, Apium graveolens L. (Dulce group) and pepper, Capsicum annuum L. were separated from ungerminated seed by density differences in a sucrose and water solution. The top (floating) fraction in both species had the highest percentage germination and percent and rate of emergence compared to either the bottom fraction or unseparated seed.

‘Migold’ is a sweet, pointed bell pepper (Capsicum annuum L.) with yellow immature fruit that ripen to an orange-red color. It is a week earlier than ‘Romanian’ and is adapted to the northern United States. The fruit have been satisfactorily processed as a pickled product. Although initially developed for the pickling trade, ‘Migold’ is also well-suited for fresh market use, the garden, and as parents for breeding programs.