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Sodium tanshinone IIA sulphate (STS) is a product originated from Salvia miltiorrhiza Bunge [Lamiaceae], which exerts an antitumour effect. However, the role of STS on lung adenocarcinoma (LUAD) remains unexplored. Our study explores the effect and mechanism of STS against LUAD. LUAD cells were treated with 100 μM STS for 24 h and control group cells were cultured under normal medium conditions. Functionally, the viability, migration, invasion and angiogenesis of LUAD cells were examined by MTT, wound healing, transwell and tube formation assay, respectively. Moreover, cells were transvected with different transfection plasmids. Dual luciferase reporter and RNA immunoprecipitation (RIP) assays were used to verify the relationship between miR-874 and eEF-2K. STS significantly decreased the viability (40–50% reduction), migration (migration rate of A549 cells from 0.67 to 0.28, H1299 cells from 0.71 to 0.41), invasion (invasion numbers of A549 cells from 172 to 55, H1299 cells from 188 to 35) and angiogenesis (80-90% reduction) of LUAD cells. Downregulation of miR-874 partially abolished the antitumour effect of STS. EEF-2K was identified to be the target of miR-874, and its downregulation markedly abolished the effects of miR-874 downregulation on tumourigenesis of LUAD. Moreover, silencing of TG2 abrogated eEF-2K-induced progression of LUAD. STS attenuated the tumourigenesis of LUAD through the mediation of the miR-874/eEF-2K/TG2 axis. STS is a promising drug to fight against lung cancer, which might effectively reverse drug resistance when combined with classical anticancer drugs. [ABSTRACT FROM AUTHOR]

This study investigates the performance of recycled aggregate concrete incorporating different sizes and concentrations of coarse aggregate under sodium sulphate and normal water curing. Ten mixes were produced, having two control mixes of 12 to 20 mm and 5 to 12 mm coarse aggregate size. The rest of the mixes have supplementary cementitious material with 0%, 15%, 30%, and 45% substitution of respective sizes normal aggregate by recycled aggregate. The fresh recycled aggregate concrete mixes were assessed through the slump, ball penetration, and compacting factor test, which exhibited a falling trend with the percentage increase of recycled aggregate. Moreover, compressive strength and ultrasonic pulse velocity drop with the percentage of RCA increases at 7, 28, and 91-days normal curing and 5% Na2SO4 solution curing at 91 days. The compressive strength and ultrasonic pulse velocity of 5-12 mm coarse aggregate concrete showed improvement over 12-20 mm coarse aggregate concrete of the same replacement for both curing. However, 5% Na2SO4 solution curing specimens exhibit around 5-11% decrease in compressive strength and higher penetration depth than normal curing . Furthermore, the outer face of the silica fume included samples have received fewer white patches after sodium sulphate immersion. [ABSTRACT FROM AUTHOR]

This paper identifies the critical cement parameters that cause expansive delayed ettringite formation (DEF) and compares them with Australian cement standards and specifications. The comparison shows that general-purpose (GP) cements adhering to Standards Australia and specifications stipulating low sulphate, alkali contents may not be prone to expansive DEF. However, there is a lack of experimental evidence supporting the low risk of Australian cements for expansive DEF. Hence, in this study, the susceptibility of Australian GP cements to expansive DEF under different heat curing temperatures up to 90°C have been studied. Further, these cements have been chemically modified to simulate the characteristics of cements used where deleterious DEF is observed in field cases. The testing protocol included long-term mortar expansion studies supported by phase and microstructural analyses. The results indicate that mortars containing Australian GP cements do not exhibit DEF expansion. Furthermore, increasing the cement sulphate content to 4% or alkali content to 1% did not result in DEF expansion. However, for cements where both the sulphate and alkali contents were increased to 4% and 1%, respectively, mortars generated significant expansion associated with ettringite precipitation. Overall, the results obtained from this study indicate that GP cements complying with Standards Australia and specifications for sulphate and alkali limits are not susceptible to expansive DEF. [ABSTRACT FROM AUTHOR]

Diabetes mellitus is one of the most concerning conditions, and its chronic consequences are almost always accompanied by infection, oxidative stress, and inflammation. Reducing excessive reactive oxygen species and the wound's inflammatory response is a necessary treatment during the acute inflammatory phase of diabetic wound healing. Malva sylvestris extract (MS) containing nanofibers containing neomycin sulfate (NS) were synthesized for this investigation, and their impact on the healing process of diabetic wounds was assessed. Using Design Expert, the electrospinning process for the fabrication of NS nanofibers (NS-NF) was adjusted for applied voltage (X1), the distance between the needle's tip and the collector (X2), and the feed rate (X3) for attaining desired entrapment efficacy [EE] and average nanofiber diameter (ND). The optimal formulation can be prepared with 19.11 kV of voltage, 20 cm of distance, and a flow rate of 0.502 mL/h utilizing the desirability approach. All the selected parameters and responses have their impact on drug delivery from nanofibers. In addition, M. sylvestris extracts have been added into the optimal formulation [MS-NS-NF] and assessed for their surface morphology, tensile strength, water absorption potential, and in vitro drug release studies. The NS and MS delivery from MS-NS-NF has been extended for more than 60 h. M. sylvestris-loaded nanofibers demonstrated superior antibacterial activity compared to plain NS nanofibers. The scaffolds featured a broad aspect and a highly linked porous fibrous network structure. Histomorphometry study and the in vitro scratch assay demonstrate the formulation's efficacy in treating diabetic wound healing. The cells treated with MS-NS-NF in vivo demonstrated that wound dressings successfully reduced both acute and chronic inflammations. To improve the healing of diabetic wounds, MS-NS-NF may be regarded as an appropriate candidate for wound dressing. [ABSTRACT FROM AUTHOR]

The impact of p-cresyl sulfate (PCS) and indoxyl sulfate (IS) on the prognosis of patients with uremia remains controversial. We performed a prospective study on peritoneal dialysis (PD) to investigate the relationship between PCS or IS levels with clinical outcomes. This prospective cohort study investigated the association of serum PCS and IS with clinical outcomes in patients undertaking PD. We performed a correlations analysis to explore the influencing factors of PCS an IS. Meta-analysis was conducted to objectively evaluate the prognostic effects of PCS and IS on different stages of CKD patients. A total of 127 patients were enrolled consecutively and followed with an average period of 51.3 months. Multivariate Cox regression showed that serum total PCS not only contributed to the occurrence of PD failure event (HR: 1.05, 95% CI = 1.02 to 1.07, p < 0.001), but also increased the risk of cardiovascular event (HR: 1.08, 95% CI = 1.04 to 1.13, p < 0.001) and PD-associated peritonitis (HR: 1.04, 95% CI = 1.02 to 1.08, p = 0.001). Dividing the total PCS level by 18.99 mg/L, which was calculated from the best cutoff value of the ROC curve, patients with total PCS higher than 18.99 mg/L had worse prognosis. Meta-analysis confirmed its value in cardiovascular event in PD. The serum total PCS concentration was a detrimental factor for higher PD failure event, cardiovascular event, and PD-associated peritonitis. It could be used as an innovative marker in predicting poor clinical outcome in PD. [ABSTRACT FROM AUTHOR]

Understanding how individual pollution sources contribute to ambient sulfate pollution is critical for assessing past and future air quality regulations. Since attribution to specific sources is typically not encoded in spatial air pollution data, we develop a mechanistic model which we use to estimate, with uncertainty, the contribution of ambient sulfate concentrations attributable specifically to sulfur dioxide (SO2) emissions from individual coal-fired power plants in the central United States. We propose a multivariate Ornstein–Uhlenbeck (OU) process approximation to the dynamics of the underlying space-time chemical transport process, and its distributional properties are leveraged to specify novel probability models for spatial data that are viewed as either a snapshot or time-averaged observation of the OU process. Using US EPA SO2 emissions data from 193 power plants and state-of-the-art estimates of ground-level annual mean sulfate concentrations, we estimate that in 2011—a time of active power plant regulatory action—existing flue-gas desulfurization (FGD) technologies at 66 power plants reduced population-weighted exposure to ambient sulfate by 1.97 μg/m3 (95% CI: 1.80–2.15). Furthermore, we anticipate future regulatory benefits by estimating that installing FGD technologies at the five largest SO2-emitting facilities would reduce human exposure to ambient sulfate by an additional 0.45 μg/m3 (95% CI: 0.33–0.54). for this article are available online. [ABSTRACT FROM AUTHOR]

Atmospheric aerosols containing ammonium sulfate have several morphological types in the solid phase. Laboratory experiments were used to reproduce the particle shapes commonly found in atmospheric samples to elucidate factors affecting these different particle shapes. Ammonium sulfate particles and mixed particles with oxalate were prepared under different relative humidity (RH) conditions and were observed using transmission electron microscopy (TEM). Most ammonium sulfate particles dried using a diffusion dryer after generation from aqueous solution were spherical or clusters of spherical units. However, after exposure of the TEM samples to 59% RH and 75% RH at atmospheric pressure, some particles changed to a rotundate-rectangular shape with parallel straight lines as the particle perimeter. Number fractions of particles that had changed to rotundate-rectangular shape from a spherical shape at 59% RH and 75% RH were, respectively, 6% and 52% at 3 h, and 18% and 66% at 1 day. Morphological changes during the experiment suggest that ammonium sulfate crystallization occurred under metastable RH. Morphological changes to rotundate-rectangular shapes were also found for ammonium sulfate co-existing with oxalate. These results indicate that spherical or complexly shaped sulfate-containing aerosols can change gradually to shapes having more regular structures according to a particle's experienced RH condition. Both spherical and rotundate-rectangular shapes of sulfate particles have often been found in atmospheric aerosol samples. The morphological change of ammonium sulfate found in this study will be useful to infer the optical properties of atmospheric particles and the thermodynamic process on a solid particle surface. [ABSTRACT FROM AUTHOR]

Cleaning and disinfection of dairy equipment is essential to ensure the hygienic quality of milk. Occasionally, some farmers use washing-up liquids and disinfectants for home use, especially when cleaning procedures are carried out manually. Residues of detergents and disinfectants in milk may interfere with the response of microbial inhibitor tests used for screening antibiotics in milk. Therefore, the aim of this study was to evaluate the interference of non-specific detergents in screening tests (BRT MRL; Delvotest SP-NT MCS; Eclipse 100) for goat's milk. Twelve replicates of eight concentrations of five washing-up liquids (0–1%) and one disinfectant (0–1%) were analysed. The results showed that the presence of washing-up liquids at concentrations of ≥1 ml/l leads to positive results in microbial tests. In particular, the product containing sodium laureth sulphate and ethanol produced the largest number of positive outcomes. The presence of disinfectant based on sodium hypochlorite did not affect the test response. The detection capabilities of microbial inhibitor tests for penicillins were also studied in milk with and without cleaning products, calculating the dose–response curve with eight concentrations of amoxicillin, ampicillin, benzylpenicillin and cloxacillin, respectively. The detection limits of the screening tests for penicillins were not modified substantially by the cleaning product based on sodium laureth sulphate and ethanol. Residues of cleaning agents in milk can be avoided when specific detergents and disinfectants for milking equipment are used and good cleaning practices are applied. [ABSTRACT FROM PUBLISHER]

Alkylaminium sulfates are frequently detected in ambient aerosols, and are believed to be important in the nucleation of new particles in the atmosphere, despite the comparatively low gas phase concentrations of amines. In this study, water activities and osmotic coefficients have been measured, using a chilled mirror dew point technique, of aqueous mixtures of sulfuric acid and the following alkylaminium sulfates: methylaminium, ethylaminium, dimethylaminium, diethylaminium, and trimethylaminium sulf-ate. The samples were prepared by mixing solutions of the five corresponding amines and aqueous sulfuric acid and determining the exact aminium to sulfate molar ratios by ion chromatography. The results were correlated using an extended Zdanovskii–Stokes–Robinson equation to enable concentration/water activity rela-tionships to be calculated over the entire composition range from pure aqueous sulfuric acid to pure aqueous aminium sulfate. Water activities and osmotic coefficients for aminium:sulfate ratios of 1:1 (the bisulfate salts) and lower showed great similarity with ammonium bisulfate, but osmotic coefficients for the 2:1 ratio (the aminium sulfates) were significantly larger (and water activities lower) than for ammonium sulfate. These results differ from those obtained in Clegg et al.'s (2013) study. The relative values of the osmotic coefficients, in concentrated solutions, suggest that the numbers of methyl or ethyl groups in the aminium ion may have a stronger lowering effect on water activity than the alkyl chain length. Copyright 2015 American Association for Aerosol Research [ABSTRACT FROM PUBLISHER]

This investigation focuses on the characterisation of the aerosol particle hygroscopicity. Aerosol particle optical properties were measured at Granada, Spain, during winter and spring seasons in 2013. Measured optical properties included particle light-absorption coefficient (sa p ) and particle light-scattering coefficient (ss p ) at dry conditions and at relative humidity (RH) of 85 +10%. The scattering enhancement factor, f(RH = 85%), had a mean value of 1.5 + 0.2 and 1.6 + 0.3 for winter and spring campaigns, respectively. Cases of high scattering enhancement were more frequent during the spring campaign with 27% of the f(RH =85%) values above 1.8, while during the winter campaign only 8% of the data were above 1.8. A Saharan dust event (SDE), which occurred during the spring campaign, was characterised by a predominance of large particles with low hygroscopicity. For the day when the SDE was more intense, a mean daily value of f(RH = 85%) = 1.3 + 0.2 was calculated. f(RH = 85%) diurnal cycle showed two minima during the morning and afternoon traffic rush hours due to the increase in non-hygroscopic particles such as black carbon and road dust. This was confirmed by small values of the single-scattering albedo and the scattering Angstrom exponent. A significant correlation between f(RH =85%) and the fraction of particulate organic matter and sulphate was obtained. Finally, the impact of ambient RH in the aerosol radiative forcing was found to be very small due to the low ambient RH. For high RH values, the hygroscopic effect should be taken into account since the aerosol forcing efficiency changed from - 1 3 W/m² at dry conditions to - 17 W/m² at RH = 85%. [ABSTRACT FROM AUTHOR]

This study was carried out from 2003 to 2007 to understand the hydrogeochemical processes and the solute sources of the meltwaters of the Chhota Shigri Glacier, Himalaya. The meltwater is almost neutral to slightly alkaline in nature: bicarbonate and sulphate are the dominant anions, while calcium and magnesium are the dominant cations. Bicarbonate is found to be derived from carbonate weathering and partly from silicate weathering. Rock weathering followed by precipitation are the main controlling factors that influence the meltwater chemistry of this region. The relatively high values of pCO2 reflect a higher rate of solubility in comparison to release of excess CO2 gas to the atmosphere. The presence of active hydrogeochemical processes and sediment–water interaction results in excess solute transport through the meltwater to the Chandra River that feeds the Chenab, one of the great Himalayan river systems, and ultimately flows into the ocean. This study is the first of its kind to understand in detail the hydrogeochemical process and resultant solute load transport in this Himalayan glacier. Citation Sharma, P., Ramanathan, A.L., and Pottakkal, J., 2013. Study of solute sources and evolution of hydrogeochemical processes of the Chhota Shigri Glacier meltwaters, Himachal Himalaya, India. Hydrological Sciences Journal, 58 (5), 1128–1143. Editor Z.W. Kundzewicz [ABSTRACT FROM AUTHOR]

A numerical technique is presented whereby aquifer hydraulic diffusivities (D) and macrodispersivities (α) are calculated by linear equations rewritten from flow and solute transport differential equations. The approach requires a GIS to calculate spatial and temporal hydraulic head (h) and solute concentration gradients. The model is tested in Portugal, in a semi-confined aquifer periodically monitored forhand chloride/sulphate concentrations. AverageD(0.46 m2/s) and α (1975 m) compare favourably with literature results. The relationship between α and scale (L) is also investigated. In this context, two aquifer groups could be identified: the first group is heterogeneous at the “macroscopic” scale (solute travelled distances <1 km), but homogeneous at the “megascopic” scale. The overall scale dependency in this case is given by an equation of logarithmic type. The second group is heterogeneous at the macroscopic and megascopic scales, with a scale dependency of linear type. Citation Pacheco, F.A.L., 2013. Hydraulic diffusivity and macrodispersivity calculations embedded in a geographic information system.Hydrological Sciences Journal, 58 (4), 930–944. [ABSTRACT FROM AUTHOR]

In recent years, Aerodyne aerosol mass spectrometers (AMS) have been used in many locations around the world to study the size-resolved, nonrefractory chemical composition of ambient particles. In order to obtain quantitative data, the mass or (number) of particles detected by the AMS relative to the mass (or number) of particles sampled by the AMS, i.e., the AMS collection efficiency (CE) must be known. Previous studies have proposed and used parameterizations of the AMS CE based on the aerosol composition and sampling line relative humidity. Here, we evaluate these parameterizations by comparing AMS mass concentrations with independent measurements of fine particle volume or particle-into-liquid sampler (PILS) ion chromatography measurements for 3 field campaigns with different dominant aerosol mixtures: (1) acidic sulfate particles, (2) aerosol containing a high mass fraction of ammonium nitrate, and (3) aerosol composed of primarily biomass burning emissions. The use of the default CE of 0.5 for all campaigns resulted in 81–90% of the AMS speciated and total mass concentrations comparing well with fine particle volume or PILS measurements within experimental uncertainties, with positive biases compared with a random error curve. By using composition-dependent CE values (sometimes as a function of size) which increased the CE for the above aerosol types, the fraction of data points within the measurement uncertainties increased to more than 92% and the mass concentrations decreased by ∼5–15% on an average. The CE did not appear to be significantly dependent on changes in organic mass fraction although it was substantial in the 3 campaigns (47, 30, and 55%). [ABSTRACT FROM AUTHOR]

This paper aims at characterising the impact of the atmospheric variability on the aerosol burden and residence time in the Arctic region. For this purpose, a global simulation using an emissions inventory from the year 2000 is performed for the period 2000-2005. The model thus describes a 6-yr evolution of sulphate, black carbon (BC) and mineral dust, whose variability is driven by the atmosphere only. Our simulation is validated, thanks to comparisons with surface observations. The aerosol residence time takes minimum values in fall: 4 d for sulphate and 8 d for BC and dust. It takes maximum values in June: 10 d for sulphate and 16 d for BC and dust. However, from one spring to another, it can vary by about 50% for sulphate, 40% for BC and 100% for dust, depending on the atmospheric variability. In June, sulphate, BC and dust burden averaged over the Arctic region reach respectively maximums of 1.9 mg[S]m-2, 0.2 mgm-2 and 6mgm-2, characteristic of the so-called Arctic haze. From one year to another, these values can vary by 20% for sulphate, 10% for BC and 60% for dust. [ABSTRACT FROM AUTHOR]

Previous work has revealed robust dorsal root ganglia neurite growth in hydrogels of chondroitin sulfate. In the current work, it was determined whether addition of a synthetic bioactive peptide could augment neurite growth in these matrices via enhanced binding and sequestering of growth factors. Fluorescence recovery after photobleaching studies revealed that addition of peptide slowed nerve growth factor diffusivity in chondroitin sulfate gels, but not in control gels of hyaluronic acid. Furthermore, cultures of chick dorsal root ganglia in gels of hyaluronic acid or chondroitin sulfate revealed enhanced growth in chondroitin sulfate gels only upon addition of peptide. Taken together, these results suggest a synergistic nerve growth factor-binding activity between this peptide and chondroitin sulfate. [ABSTRACT FROM AUTHOR]

ABSTRACT A large field experiment of the Saharan Mineral Dust Experiment (SAMUM) was performed in Praia, Cape Verde, in January and February 2008. The aerosol at Praia is a superposition of mineral dust, sea-salt, sulphates and soot. Particles smaller than 500 nm are mainly mineral dust, mineral dust-sulphate mixtures, sulphates and soot-sulphate mixtures. Particles larger then 2.5 μm consist of mineral dust, sea-salt and few mineral dust-sulphate mixtures. A transition range exists in between. The major internal mixtures are mineral dust-sulphate and soot-sulphate. Mineral dust-sea-salt mixtures occur occasionally, mineral dust-soot mixtures were not observed. The aspect ratio was 1.3-1.4 for dry particles smaller than 500 nm and 1.6-1.7 for larger ones. Parameterizations are given for dry and humid state. Although the real part of the refractive index showed low variation (1.55-1.58 at 532 nm), a multi-modal imaginary part was detected as function of particle size, reflecting the complex composition. Soot mainly influences the absorption for wavelengths longer than the haematite absorption edge, whereas for shorter wavelengths dust is dominating. The refractive index of the aerosol depends on the source region of the mineral dust and on the presence/absence of a marine component. [ABSTRACT FROM AUTHOR]

Cesium dihydrogen phosphate (CsH2PO4, CDP) and dodecaphosphotungstic acid (H3PW12O40·nH2O, WPA·nH2O) were mechanochemically milled to synthesize CDP-WPA composites. The ionic conductivities of these composites were measured by an ac impedance method under anhydrous conditions. Despite the synthesis temperatures being much lower than the dehydration and phase-transition temperatures of CDP under anhydrous conditions, the ionic conductivities of the studied composites increased significantly. The highest ionic conductivity of 6.58×10-4 Scm-1 was achieved for the 95CDP·5WPA composite electrolyte at 170 °C under anhydrous conditions. The ionic conduction was probably induced in the percolated interfacial phase between CDP and WPA. The phenomenon of high ionic conduction differs for the CDP-WPA composite and pure CDP or pure WPA under anhydrous conditions. The newly developed hydrogen interaction between CDP and WPA supports anhydrous proton conduction in the composites. [ABSTRACT FROM AUTHOR]

In this study we analyzed the sampling time effect on the overall performance of seven portable impactors (SMA MicroPortable, BioCulture, Microflow, MAS-100, Millipore Air Tester, SAS Super 180, and RCS High Flow) as well as a stationary impactor (BioStage) when collecting airborne bacteria and fungi from 2 to 30 minutes indoors and outdoors. Their performance was compared against the reference BioStage impactor collecting samples for 2 minutes. When bacteria were collected outdoors, the average concentration ratio of all test samplers relative to the reference sampler was 0.64, but it decreased to 0.04 when bacteria were collected for 2 min first and subsequently exposed to particle-free air for 28 min (30 min total sampling time). For fungi, the average concentration ratio decreased from 0.35 to 0.03 under the same conditions. When the test impactors sampled particle-free air first and then collected bioaerosols outdoors for 2 min, the concentration ratio for bacteria averaged for all test samplers decreased from 0.77 (agar plates not exposed to particle-free air and particles collected for 2 min) to 0.04 (agar plates exposed to particle-free air for 28 min first and then particles collected for 2 min). For fungi, the relative recovery averaged for all samplers decreased from 0.45 to 0.03 under the same conditions. The effects of sampling time and impactor model were statistically significant for all experimental conditions. Thus, the data obtained in this study suggest that when impactors are used for the collection of airborne bacteria and fungi, sampling times should be as short as reasonably possible to minimize the under-representation of airborne microorganism concentration which could be a factor of 10 or higher for prolonged sampling times. [ABSTRACT FROM AUTHOR]

In this paper, we examine the direct effects of sulphate and black carbon (BC) aerosols in China on East Asia monsoons and its precipitation processes by using the Community Atmosphere Model (CAM) 3.0 model. It is demonstrated that sulphate and BC aerosols in China both have the effects to weaken East Asia monsoons in both summer and winter seasons. However, they certainly differ from each other in affecting vertical structures of temperature and atmospheric circulations. Their differences are expected because of their distinct optical properties, that is, scattering versus absorbing. Even for a single type of aerosol, its effects on temperature structures and atmospheric circulations are largely season-dependent. Applications of T-test on our results indicate that forcing from BC aerosols over China is relatively weak and limited. It is also evident from our results that the effects of synthetic aerosols (sulphate and BC together) on monsoons are not simply a linear summation between these two types of aerosols. Instead, they are determined by their integrated optical properties. Synthetic aerosols to a large degree resemble effects of sulphate aerosols. This implies a likely scattering property for the integration of BC and sulphate aerosols in China. [ABSTRACT FROM AUTHOR]

Climate responses to aerosol forcing at present-day and doubled CO2-levels are studied based on equilibrium simulations with the CCM-Oslo atmospheric GCM coupled to a slab ocean. Aerosols interact on-line with meteorology through life-cycling of sulphate and black carbon (BC), and tables for aerosol optics and CCN activation. Anthropogenic aerosols counteract the warming by CO2 through a negative radiative forcing dominated by the indirect effect. Anthropogenic aerosols reduce precipitation by 4%, while CO2 doubling gives a 5% increase, mainly through enhanced convective activity, including a narrower ITCZ. Globally, the aerosol cooling is insensitive to CO2, and the effects of CO2 doubling are insensitive to aerosols. Hence, global climate responses to these sources of forcing are almost additive, although sulphate and BC burdens are slightly increased due to reduced stratiform precipitation over major anthropogenic source regions and a modified ITCZ. Regionally, positive cloud feedbacks give up to 5 K stronger aerosol cooling at present-day CO2 than after CO2 doubling. Aerosol emissions projected for year-2100 (SRES A2) strongly increase BC and change the sign of the direct effect. This results in a 0.3 K warming and 0.1% increase in precipitation compared to the year 2000, thus enhancing the global warming by greenhouse gases. [ABSTRACT FROM AUTHOR]

A new aerosol module is integrated on-line in the atmospheric GCM CAM-Oslo coupled to a slab ocean for equilibrium climate response studies. The response to an anthropogenic change in aerosols since pre-industrial times is compared with that of a future 63% increased CO2 level. The aerosol module calculates concentrations of sea-salt, mineral dust, sulphate, black carbon (BC) and particulate organic matter (POM). Look-up tables, constructed from first principles, are used to obtain optical parameters and cloud droplet numbers (CDNC) for any given aerosol composition. Anthropogenic aerosols thus produce a global near-surface cooling of 1.94 K and a 5.5% precipitation decrease, including amplifications by positive cloud feedbacks. In comparison, the CO2 increase gives a warming of 1.98 K and a 3.8% precipitation increase, causing slightly reduced sulphate, BC, POM and sea-salt burdens. A minor increase in mineral dust is ascribed to reduced subtropical precipitation downwind of Sahara over the Atlantic Ocean. The modelled indirect effects are probably overestimated, mainly due to neglected natural aerosol components and the diagnostic scheme for CDNC. Adding 15 cm−3 to CDNC everywhere reduces the indirect forcing from −2.34 to −1.36 Wm−2, whilst solving a prognostic equation for CDNC reduces it from −2.34 to −1.44 Wm−2. [ABSTRACT FROM AUTHOR]

The paper discusses some challenges in aerosol-climate modelling. CAM-Oslo, extended from NCAR-CAM3, employs an aerosol module for sea-salt, dust, sulphate, black carbon (BC) and particulate organic matter (OM). Primary aerosol size-distributions are modified by condensation, coagulation and wet-phase processes. Aerosol optics and cloud droplet numbers use look-up tables constructed from first principles. Ground level sulphate and sea-salt are generally well modelled, BC and OM are slightly underestimated (uncertain), and dust is considerably (factor ∼2) underestimated. Since non-desert dust, nitrate, anthropogenic secondary organics, and biological particles are omitted, aerosol optical depths (0.12) are underestimated by 10–25%. The underestimates are large in areas with biomass burning and soil dust. The direct and indirect forcing of aerosol increments since pre-industrial time are estimated at +0.031 Wm−2 and −1.78 Wm−2, respectively. Although the total absorption AOD probably is slightly underestimated, the BC contributes to DRF with double strength compared to the AeroCom average. Main reasons for this include: internal BC-mixing (+0.2 Wm−2), accumulation mode BC-agglomerates (+0.05 Wm−2), assumed aitken-mode OM-BC mixture (+0.1 Wm−2), large BC fraction (36%) above 500 hPa, and high low-level cloudiness. Using a prognostic CDNC and process parametrized CCN activation instead of assuming CDNC are equal to CCN, the indirect forcing is 36% smaller. [ABSTRACT FROM AUTHOR]

Investigation of centimeter-scale snow surface chemistry has been carried out at two polar sites with different site characteristics–in Dronning Maud Land, Antarctica and on the Greenland ice sheet, respectively. Large variations in both impurity content and stable oxygen isotope ratios (δ18O) were found on the submeter scale. δ18O and the concentration of nitrate correlated at both sites (r = 0.81 and 0.82, respectively). At the Antarctic site, δ18O is also correlated to concentrations of methanesulphonate (r = 0.84) and sulphate (r = 0.83) while no such correlation exists at the Greenland site. Instead, a strong anticorrelation (r =–0.85) between sulphate and methanesulphonate is found among the samples from the Greenland site. The ions correlating with δ18O at the two sites were probably deposited as acids. Our tentative explanation is that local redeposition of water vapour enriching the snow surface with the lighter isotopes is associated with simultaneous enhanced scavenging of the acids. The responsible process thereby significantly alters the chemical signals of the snow surface. [ABSTRACT FROM AUTHOR]

The Thermo Electron Model 5020 Sulfate Particulate Analyzer is a recently commercialized instrument that provides continuous measurements of the sulfate component of ambient particulate matter. The technique uses a stainless steel rod placed inside a quartz oven to reduce the particle sulfate to sulfur dioxide; followed by pulsed fluorescence detection of the sulfur dioxide. Field and laboratory evaluations of a pre-production version of the analyzer are described as well as laboratory evaluations of the pre-production version and two production units. Laboratory tests concentrated on challenging the instruments with ammonium sulfate aerosol, but tests with sodium, potassium, and calcium sulfate are reported as well. The instrument performed very well in field and laboratory settings, reporting values that were highly correlated with continuous mass measurements in the lab, and 24-hour filters in the field. Conversion/detection efficiencies for ammonium sulfate in the laboratory, and for ambient sulfate aerosol at our rural site in Addison, New York, were both very close to 80%. Laboratory conversion efficiencies for calcium, sodium, and potassium sulfate salts ranged from 4% to 63%. These lower efficiencies for mineral-type sulfates will be an important consideration in areas with significant concentrations of sea salt or mineral dust sulfate, and less important for the high sulfate Eastern US which is dominated by ammonium sulfate. [ABSTRACT FROM AUTHOR]

Single particle measurements were made in Baltimore, Maryland from March to December 2002 using a real-time single particle mass spectrometer, RSMS-3. Particle composition classes were identified that indicated how the aerosol composition changed with time. The results were compared with collocated instruments giving particle number concentrations and size distributions, sulfate, nitrate, organic, and elemental carbon mass concentrations and total mass. Examination of these measurements revealed several particulate matter (PM) events in which the 24 h averaged PM 2.5 mass exceeded 30 μ g/m 3 . Three of these events were studied in further detail by comparing number and mass concentrations obtained by RSMS-3 with standard methods. For all three events, the number concentrations obtained with RSMS-3 and a scanning mobility particle sizer were highly correlated (R 2 &nvsim; 0.7). For the event characterized by a high sulfate mass concentration, the RSMS-3 provided an accurate measure of time-dependent nitrate and carbon mass concentrations, but not for sulfate and total mass. For the two events characterized by high carbon mass concentrations (one from a transcontinental wildfire and the other from stagnation during a period of high traffic), RSMS-3 provided an accurate measure of time-dependent nitrate mass, carbon mass and total mass when the aerosol was not dominated by particles outside the size limit of RSMS-3. While the time dependencies were strongly correlated, the absolute mass or number concentrations determined by RSMS-3 were sometimes off by a constant value, which permitted the relative detection efficiencies of some particle classes to be estimated. Other factors that inhibit reconciliation of mass- and number- based concentration measurements are discussed including the difficulty of detecting ammonium sulfate by laser ablation/ionization and the varying size ranges of different particle measurement methods. [ABSTRACT FROM AUTHOR]

A field trial was carried out to compare the efficacy of the fungicides carboxin + thiram (Vitaflo®), carbendazim (Prolific®), tebuconazole (Raxil®), propiconazole (Tilt®), flutriafol + imazalil sulphate (Vincit™), and azoxystrobin (Amistar®) as seed applications for the control of head smut of sweetcorn (Zea mays), caused by the fungus Sporisporium reilianum (Sphacelotheca reiliana). The trial was carried out in the Poverty Bay region of New Zealand in a field that had a previous history of head smut. Carbendazim, flutriafol + imazalil sulphate, propiconazole, and azoxystrobin seed treatments resulted in significantly greater plant numbers and increased early plant growth compared with the untreated experimental control, carboxin + thiram, and tebuconazole treatments. Plots in the control and carboxin + thiram treatments had a relatively high number of stunted plants (<10 cm) 1 month after sowing (7.6% and 14.9% respectively). Carbendazim, tebuconazole, propiconazole, flutriafol + imazalil sulphate, and azoxystrobin seed treatments all produced low numbers of stunted plants (0.4-3.1%). Of the plants in the untreated control plots, an average of 8.7% were infected with head smut at harvest maturity. Seed treatment with carboxin + thiram did not reduce numbers of smutted plants compared with the untreated control. All other fungicides reduced the proportion of diseased plants. The most effective were propiconazole and flutriafol + imazalil sulphate, which respectively gave 2.3% and 2.4% plants infected with head smut. Carbendazim, tebuconazole, and azoxystrobin were slightly less effective reducing infection to 5-6%. Flutriafol + imazalil sulphate and propiconazole both offer alternatives to carboxin + thiram for control of head smut of sweetcorn. [ABSTRACT FROM AUTHOR]

In the presence of the anionic surfactant sodium n-dodecyl sulphate (SDS), horseradish peroxidase (HRP) undergoes a deactivation process. Suicide inactivation of horseradish peroxidase by hydrogen peroxide(3&ThickSpace;mM) was monitored by the absorbance change in product formation in the catalytic reaction cycle. The progress curve of the catalytic reaction cycle was obtained at 27°C and phosphate buffer 2.5&ThickSpace;mM The corresponding kinetic parameters i.e., intact enzyme activity (αi); the apparent rate constant of suicide inactivation by peroxide (ki); and the apparent rate constants of enzyme deactivation by surfactant (kd) were evaluated from the obtained kinetic equations. The experimental data are accounted for by the equations used in this investigation. Addition of SDS to the reaction mixture intensified the inactivation process. The deactivation ability of denaturant could be resolved from the observed inactivation effect of the suicide substrate by applying the proposed model. The results indicate that the deactivation and the inactivation processes are independent of each other. [ABSTRACT FROM AUTHOR]

Airborne data are presented on the impact of cloud processing on the aerosol mass light-scattering efficiency. The measurements, on marine stratocumulus, suggest that cloud processing significantly enhanced the mass light-scattering efficiency in three of the five cases analysed. Enhancements were of the order of 10% for air detraining from the cloud deck relative to non-detraining air. A diagnostic modelling analysis suggested that the observed enhancements were consistent with the previously proposed explanation of in-cloud sulfate production in the particle size range for efficient light scattering. [ABSTRACT FROM AUTHOR]

The Harvard Ambient Particle Concentrator (HAPC) has been used routinely for exposure testing for a period of approximately three years. The stability of concentrator performance has been investigated as a function of local meteorological conditions, ambient particle concentrations, composition, and size distribution. Concentrator performance is characterized by the concentration enrichment factor (CEF), a ratio of concentrated particle mass (or sulfate) concentration to the ambient concentration. Over three years of normal operation, the mass and sulfate CEFs averaged 27.9 and 28.6, respectively. The majority of variability in the CEF was found to be related to the mass median aerodynamic diameter (MMAD) of ambient particles and to the HAPC's total operating pressure drop. The 50% cutpoint of the HAPC is 0.15 μm. Between 0.15 and 2.5 μm, the HAPC concentrates ambient particle mass by approximately a factor of 28. It is logical that changes in particle CEF should be influenced by the amount of ambient particle mass within the concentrator's effective size range. The concentrator operates optimally at a pressure drop of 2.5 in. of water per stage. Total pressure drop ranges from 7.5-25 in. of water, depending on the alignment of the slits of the virtual impactors and other parameters. Increases in the pressure drop result in decrease of the CEF, mainly due to excessive particle loss by impaction on the edges of the collection slit. In contrast, the minor operating pressure drop was found to be consistently lower on days where neither the ambient particle mass, temperature, or relative humidity were high. This subset of days was found to have a higher CEF than days where any of the three variables were high. The HAPC minor flow pressure drops are thus monitored carefully, since they are the most controllable indicator of concentration enrichment efficiency. [ABSTRACT FROM AUTHOR]

Crystallization of sulphates in the form of gypsum and mirabilite/thenardite is one of the main causes of the accelerated disintegration of historic frescoes: The sulphur, which is necessary for these processes, may originate from a large number of different sources, Although the nature and velocity of the processes causing the damage, as well as the possible transport pathways of the salt-forming ions, can be determined with reasonable accuracy, reliable information on the origin of the ions is seldom forthcoming. Sulphur isotope ratios were determined for various construction materials and salts from the church at Eilsum (Lower Saxony, Germany) where the romanesque frescoes have suffered serious damage. The studies showed dearly that sulphate on the walls inside the church, in contrast to that on the outside walls, originates mainly from the ground beneath the church from where capillary rise takes place within the walls. This information on sources and pathways of salt-forming ions may contribute towards developing a programme of remedial measures. [ABSTRACT FROM AUTHOR]

Gypsum crusts on 18 important historical monuments in Prague were investigated from the point of view of their sulfur isotope composition. The ratio of 34S and 32S in deposited sulfates expressed in the delta unit (δ 34S) is almost constant for every monument but a significant difference occurs between monuments in the center of the city and those located on the surrounding hills. Two sets of climatic conditions in Prague have been found where different stone corrosion mechanisms occur. The enrichment of sulfate incrustation in 34S at the city center is explained in terms of the catalytic effect of other pollutants. [ABSTRACT FROM AUTHOR]

The impact of sodium dodecyl sulfate (SDS) on the protonation equilibria of 5-sulfosalicylic acid and 5-Hydroxysalicylic acid has been studied in various concentrations (0.0−2.5% w/v) of sodium dodecyl sulfate solution maintaining an ionic strength of 0.16 mol dm−3Nacl at 303 K. The protonation constants have been calculated with the computer program MINIQUAD75 and the best fit models are arrived at based on statistical grounds employing crystallographicRfactor,χ2, skewness, and kurtosis. These protonation constants values have been found to shift in micellar media as compared to those in pure water. The differences in the values have been attributed to the solvent properties of the interfacial and bulk phases involving contribution from the micellar surface potential in the case of charged micelles. The trend of log values of stepwise protonation constants with mole fraction of the medium have been explained based on electrostatic and non-electrostatic forces operating on the protonation equilibria. Distributions of species, protonation equilibria, and effect of influential parameters on the protonation constants have also been presented. [ABSTRACT FROM PUBLISHER]