An examination of chemistry and transport processes in the tropical lower stratosphere using observations of long-lived and short-lived compounds obtained during STRAT and POLARIS

A suite of compounds with a wide range of photochemical lifetimes (3 months to several decades) was measured in the tropical and midlatitude upper troposphere and lower stratosphere during the Stratospheric Tracers of Atmospheric Transport (STRAT) experiment (fall 1995 and winter, summer, and fall 1996) and the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) deployment in late summer 1997. These species include various chlorofluorocarbons, hydrocarbons, halocarbons, and halons measured in whole air samples and CO measured in situ by tunable diode laser spectroscopy. Mixing ratio profiles of long-lived species in the tropical lower stratosphere are examined using a one-dimensional (1-D) photochemical model that includes entrainment from the extratropical stratosphere and is constrained by measured concentrations of OH. Profiles of tracers found using the 1-D model agree well with all the observed tropical profiles for an entrainment time scale of 8.5-4+6 months, independent of altitude between potential temperatures of 370 and 500 K. The tropical profile of CO is used to show that the annually averaged ascent rate profile, on the basis of a set of radiative heating calculations, is accurate to approximately ±44%, a smaller uncertainty than found by considering the uncertainties in the radiative model and its inputs. Tropical profiles of ethane and C2Cl4 reveal that the concentration of Cl is higher than expected on the basis of photochemical model simulations using standard gas phase kinetics and established relationships between total inorganic chlorine and CFC-11. Our observations suggest that short-lived organic chlorinated compounds and HCl carried across the tropical tropopause may provide an important source of inorganic chlorine to the tropical lower stratosphere that has been largely unappreciated in previous studies. The entrainment timescale found here is considerably less than the value found by a similar study that focused on observations obtained in the lower stratosphere during 1994. Several possible explanations for this difference are discussed. Copyright 1999 by the American Geophysical Union

Selective labelling of arginine residues in protein sulfated glycosaminoglycan binding sites

In animals, the interaction of numerous proteins with glycosaminoglycans (GAGs) regulates many aspects of their functions, and so organism development and homeostasis, as well many related pathologies. The interactions between the GAG heparan sulfate (HS) and the fibroblast growth factors (FGFs) have become a major paradigm for how such interactions regulate biological outcomes. Thus, binding HS controls FGF stability, its diffusion between cells and the generation of intracellular signals via the cognate FGF receptors (FGFRs). The basic arginine and lysine amino acids on the surface of FGFs have an important role in binding the polysaccharide via its numerous sulfate and carboxyl groups. Indeed electrostatic bonds between FGF and GAG dominate the interaction, at least kinetically. However, the contribution of arginine residues on the protein surface to GAG binding has generally not been established. This has been addressed directly in this thesis. A means to selectively label and so identify arginine side chains involved in binding heparin as an approximation for cellular GAGs was developed and evaluated, using the two most studied FGFs, FGF1 and FGF2. Two chemicals which selectively and specifically react with the guanidino group of arginine, phenylglyoxal (PGO) and hydroxyphenylglyoxal (HPG) were chosen for the purpose of this work. By combining mass spectrometry and an automatic programming language, the multiple products of PGO’s reaction with arginine were readily deconvoluted. The method was then applied to the other thirteen paracrine FGFs, which were produced as recombinant proteins. In addition, lysine selective labelling data were acquired for those FGFs where this was lacking. Thus, a complete description of the surface electrostatic map on fifteen paracrine FGFs guiding heparin engagement was obtained. The addition of arginine residues into the map of binding makes adjustments to the definition of heparin binding sites (HBSs) in some FGFs, for instance, FGF4. The refinement of the assignment of residues to secondary HBSs is consistent with data obtained by others on the ability of particular FGFs (FGF4, FGF6, FGF17, FGF18 and FGF10) to cross-link HS chains. In addition, the data raise some interesting properties of GAG binding, for example, the dual specificity of the secondary heparin binding site, HBS-3, in some FGFs, which is also involved in binding the FGFR. While the results generally support the idea that the conservation of structures for GAG binding in FGFs is related to their evolutionary divergence, it also suggests that changes in the structures in GAG binding may in some instances have diverged more rapidly since an amino acid substitution between members of a subfamily enables a significant alteration in heparin engagement. This suggests that in some instances, changes to the heparin binding properties of an FGF may contribute to a diversification of function within a subfamily. A further method was developed, whereby the entire selective labelling was done in solution, without the need for a heparin affinity column. The method was applied to the interactions of members of the FGF7 subfamily (FGF3, FGF7, and FGF10) with heparin, followed by chondroitin sulfate (CS), dermatan sulfate (DS). This allowed the analysis of lysine residues involved in binding physiologically relevant GAGs rather than heparin. Finally, the wider applicability of the method was acquired by determining the lysine and arginine residues that bind heparin in a ‘phage display antibody’, HS4C3. Due to the selectivity of HS4C3 for anticoagulant structures in heparin through its CDR3 loop, it was possible to use the data to propose a means to model protein-GAG binding. This was demonstrated using the knowledge of the binding specificity of HS4C3 for 3-O-sulfate and the positions of residues identified by the selective labelling. Taken together, the work in this thesis provides new insight into the involvement of arginine and lysine residues in the engagement of proteins to GAGs. This may enable future ‘omics’ approaches to identify GAG binding sites in proteins in cells and tissues, and to predict from principles where such sites are on a protein surface

A new interpretation of total column BrO during Arctic spring

Emission of bromine from sea-salt aerosol, frost flowers, ice leads, and snow results in the nearly complete removal of surface ozone during Arctic spring. Regions of enhanced total column BrO observed by satellites have traditionally been associated with these emissions. However, airborne measurements of BrO and O3 within the convective boundary layer (CBL) during the ARCTAS and ARCPAC field campaigns at times bear little relation to enhanced column BrO. We show that the locations of numerous satellite BrO "hotspots" during Arctic spring are consistent with observations of total column ozone and tropopause height, suggesting a stratospheric origin to these regions of elevated BrO. Tropospheric enhancements of BrO large enough to affect the column abundance are also observed, with important contributions originating from above the CBL. Closure of the budget for total column BrO, albeit with significant uncertainty, is achieved by summing observed tropospheric partial columns with calculated stratospheric partial columns provided that natural, short-lived biogenic bromocarbons supply between 5 and 10 ppt of bromine to the Arctic lowermost stratosphere. Proper understanding of bromine and its effects on atmospheric composition requires accurate treatment of geographic variations in column BrO originating from both the stratosphere and troposphere. Copyright 2010 by the American Geophysical Union

Integration of decision support systems to improve decision support performance

Decision support system (DSS) is a well-established research and development area. Traditional isolated, stand-alone DSS has been recently facing new challenges. In order to improve the performance of DSS to meet the challenges, research has been actively carried out to develop integrated decision support systems (IDSS). This paper reviews the current research efforts with regard to the development of IDSS. The focus of the paper is on the integration aspect for IDSS through multiple perspectives, and the technologies that support this integration. More than 100 papers and software systems are discussed. Current research efforts and the development status of IDSS are explained, compared and classified. In addition, future trends and challenges in integration are outlined. The paper concludes that by addressing integration, better support will be provided to decision makers, with the expectation of both better decisions and improved decision making processes

Reduced pollution level and ecological risk of mercury-polluted sediment in a alkali-chlorine factory's brine water storage pond after corrective actions: A case study in Southern Taiwan

Mercury is a highly toxic pollutant and persistent in the sediment, which highlights the needs for remediation of sediment Hg pollution. However, the effects of remedial actions on the pollution and ecological risk of Hg in sediment are less investigated. Therefore, this study conducted an environmental risk assessment before and after corrective actions in the brine water storage pond of a closed alkali-chlorine plant with high Hg pollution in the sediment. The results showed that the accumulation of Hg in the sediment (2.59–443 mg/kg), fish and crabs (1.10–8.54 mg/kg) in the polluted pond was higher than the regulation limit in Taiwan. After implementing the corrective actions such as institutional/engineering control and remediation, we found that the Hg concentration and pollution factor (CF), in the sediment were significantly decreased by 74% and 73% (p=0.02), respectively. In addition, the geoaccumulation index (I-geo) were decreased to lower pollution class after corrective actions (p=0.009). The risk related indices such as potential ecological risk index (RI) and risk quotient (RQ) also showed significant decreases (p=0.03) after corrective actions (71% and 73%, respectively). Although the values of pollution and risk indices were still high after remediation, the results of this study demonstrated the effectiveness of corrective actions on amelioration of sediment Hg pollution. It suggests that corrective actions should be continuously implemented to reduce the pollution and risk levels in all aspects to an acceptable level for stakeholders

Field evaluation of the establishment potential of wMelPop Wolbachia in Australia and Vietnam for dengue control

Introduced Wolbachia bacteria can influence the susceptibility of Aedes aegypti mosquitoes to arboviral infections as well as having detrimental effects on host fitness. Previous field trials demonstrated that the wMel strain of Wolbachia effectively and durably invades Ae. aegypti populations. Here we report on trials of a second strain, wMelPop-PGYP Wolbachia, in field sites in northern Australia (Machans Beach and Babinda) and central Vietnam (Tri Nguyen, Hon Mieu Island), each with contrasting natural Ae. aegypti densities.Mosquitoes were released at the adult or pupal stages for different lengths of time at the sites depending on changes in Wolbachia frequency as assessed through PCR assays of material collected through Biogents-Sentinel (BG-S) traps and ovitraps. Adult numbers were also monitored through BG-S traps. Changes in Wolbachia frequency were compared across hamlets or house blocks.Releases of adult wMelPop-Ae. aegypti resulted in the transient invasion of wMelPop in all three field sites. Invasion at the Australian sites was heterogeneous, reflecting a slower rate of invasion in locations where background mosquito numbers were high. In contrast, invasion across Tri Nguyen was relatively uniform. After cessation of releases, the frequency of wMelPop declined in all sites, most rapidly in Babinda and Tri Nguyen. Within Machans Beach the rate of decrease varied among areas, and wMelPop was detected for several months in an area with a relatively low mosquito density.These findings highlight challenges associated with releasing Wolbachia-Ae. aegypti combinations with low fitness, albeit strong virus interference properties, as a means of sustainable control of dengue virus transmission

Long-term effects of tongue piercing — a case control study

The aim of this study was to evaluate tooth and periodontal damage in subjects wearing a tongue piercing (TP) in comparison to matched control subjects without tongue piercing. Members of the German Federal Armed Forces who had TP (group TP) and a matched control group (group C) volunteered to take part in the study. The time in situ, localization and material of TP were documented. Dental examinations included DMF-T, oral hygiene, enamel fissures (EF), enamel cracks (EC) and recessions. Statistical analysis was determined by χ2 test and the t test. Both groups had 46 male subjects (mean age 22.1 years). The piercings had been in situ for 3.8 ± 3.1 years. Subjects in the TP group had a total of 1,260 teeth. Twenty-nine subjects had 115 teeth (9.1%) with EF (67% lingual). In group C (1,243 teeth), 30 subjects had 60 teeth with EF (4.8%, 78% vestibular) (p < 0.01). Thirty-eight subjects belonging to group TP had EC in 186 teeth (15%). In group C, 26 subjects with 56 teeth (4.5%) were affected by EC (p < 0.001). Twenty-seven subjects in group TP had 97 teeth (7.7%) with recessions. Lingual surfaces of anterior teeth in the lower jaw were affected most frequently (74%). In group C, 8 subjects had 19 teeth (1.5%) with recessions (65% vestibular). Differences between the two groups were statistically significant (p < 0.001). Tongue piercing is correlated with an increased occurrence of enamel fissures, enamel cracks and lingual recessions. Patients need better information on the potential complications associated with tongue piercing

A Meta-Analysis of the Existing Knowledge of Immunoreactivity against Hepatitis C Virus (HCV)

Approximately 3% of the world population is infected by HCV, which represents a major global health challenge. Almost 400 different scientific reports present immunological data related to T cell and antibody epitopes derived from HCV literature. Analysis of all HCV-related epitope hosted in the Immune Epitope Database (IEDB), a repository of freely accessible immune epitope data, revealed more than 1500 and 1900 distinct T cell and antibody epitopes, respectively. The inventory of all data revealed specific trends in terms of the host and the HCV genotypes from which sequences were derived. Upon further analysis we found that this large number of epitopes reflects overlapping structures, and homologous sequences derived from different HCV isolates. To access and visualize this information we developed a novel strategy that assembles large sets of epitope data, maps them onto reference genomes and displays the frequency of positive responses. Compilation of the HCV immune reactivity from hundreds of different studies, revealed a complex and thorough picture of HCV immune epitope data to date. The results pinpoint areas of more intense reactivity or research activities at the level of antibody, CD4 and CD8 responses for each of the individual HCV proteins. In general, the areas targeted by the different effector immune functions were distinct and antibody reactivity was positively correlated with hydrophilicity, while T cell reactivity correlated with hydrophobicity. At the sequence level, epitopes frequently recognized by both T cell and B cell correlated with low variability, and our analysis thus highlighted areas of potential interest for practical applications. The human reactivity was further analyzed to pinpoint differential patterns of reactivity associated with acute versus chronic infection, to reveal the apparent impact of glycosylation on T cell, but not antibody responses, and to highlight a paucity of studies involved antibody epitopes associated with virus neutralization