Interfacial characteristics of BIOfactor MTA and Biodentine with dentin.

The objective of this study was to characterize the interface between dentin and MTA-Angelus (Angelus, Londrina, Brasil), Biodentine (Septodont, France) and BIOfactor MTA (Imicryl, Konya, Turkey) using scanning electron microscopy (SEM), energy disperse X-ray spectroscopy (SEM-EDS) and confocal laser scanning microscopy (CLSM). Fifteen dentin segments were obtained from previously extracted single-rooted human teeth. Canal lumens were instrumented with diamond burs and then randomly filled with MTA-Angelus, Biodentine or BIOfactor MTA and placed in distilled water or Hanks' Balanced Salt Solution (HBSS) for 28-days. The samples were examined with SEM and the thickness of the interfacial layer measured. SEM-EDS analysis was performed to determine principal elemental composition of the material, dentin, and interfacial area. The marginal adaptation of cements to dentin was assessed by confocal microscopy and the percentage of material penetration was calculated. An interfacial layer was evident in approximately 70% of SEM images in both MTA-Angelus and BIOfactor samples. The thickness of interfacial layer was significantly higher in HBSS than in distilled water for all groups. MTA Angelus resulted in the thickest interfacial layer in distilled water while Biodentine had the thickest interfacial layer in HBSS. Calcium levels within the BIOfactor MTA-dentin interface were higher than both dentin and cement. Dentin penetration was higher in BIOfactor MTA and silicon was evident in all material-dentin interfaces. All calcium silicate-based materials promoted the formation of an interfacial layer. BIOfactor MTA exhibited promising characteristics with its good marginal adaptation even though it presented a moderately thick interfacial layer. RESEARCH HIGHLIGHTS: A distinguishable interfacial layer was observed in most of the samples within the BIOfactor MTA, MTA-Angelus and Biodentine groups. The elemental constitution of the interfacial layer was different from that of the calcium silicate based materials.

Analysis of the Distribution of Total Phosphine and the Characteristics of Phosphine Poisoning in 29 Victims.

OBJECTIVES: To study the distribution of total phosphine in phosphine poisoning victims and summarize the characteristics of phosphine poisoning cases. METHODS: The phosphine and its metabolites in the biological samples of 29 victims in 16 phosphine poisoning cases were qualified and quantified by headspace gas chromatography-mass spectrometry. RESULTS: Five victims among 29 were poisoned by ingestion of aluminium phosphide and 24 by inhalation of phosphine gas. Phosphine metabolites were detected in the biological samples of 23 victims, and the concentrations of total phosphine in blood ranged 0.5-34.0 µg/mL. The total concentration of phosphine in liver tissue was up to 71.0 µg/g. Phosphine was not detected in the blood of the other six survived victims, which may be related to the small amount of phosphine exposure and the delay in blood sampling. CONCLUSIONS: The total concentration of phosphine in blood and tissues caused by aluminum phosphine ingestion is higher than that caused by phosphine gas inhalation. The death cases of phosphine inhalation are characterized by long exposure time, repeated exposures and age susceptibility.

Analysis of the Distribution of Total Phosphine and the Characteristics of Phosphine Poisoning in 29 Victims / 法医学杂志

OBJECTIVES@#To study the distribution of total phosphine in phosphine poisoning victims and summarize the characteristics of phosphine poisoning cases.@*METHODS@#The phosphine and its metabolites in the biological samples of 29 victims in 16 phosphine poisoning cases were qualified and quantified by headspace gas chromatography-mass spectrometry.@*RESULTS@#Five victims among 29 were poisoned by ingestion of aluminium phosphide and 24 by inhalation of phosphine gas. Phosphine metabolites were detected in the biological samples of 23 victims, and the concentrations of total phosphine in blood ranged 0.5-34.0 μg/mL. The total concentration of phosphine in liver tissue was up to 71.0 μg/g. Phosphine was not detected in the blood of the other six survived victims, which may be related to the small amount of phosphine exposure and the delay in blood sampling.@*CONCLUSIONS@#The total concentration of phosphine in blood and tissues caused by aluminum phosphine ingestion is higher than that caused by phosphine gas inhalation. The death cases of phosphine inhalation are characterized by long exposure time, repeated exposures and age susceptibility.

Rapid trace element analysis of microgram soft materials with cryogenic milling and laser ablation spectroscopy.

Trace element analysis of soft materials, to determine the content of low concentration elements, is important in many industries such as food quality control and medical biopsy analysis. Many of these applications would benefit from faster analysis with smaller sample requirements. Further, some natural samples are soft and have high water content, which brings challenges to element analysis. Here, we develop a cryogenic pelletization pretreatment to address those challenges. The soft samples are cryogenically milled, freeze-dried, and pelletized before elemental analysis. Analysis is performed by laser ablation spectroscopy, the combination of laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS), to rapidly analyze light and heavy analytes. For this initial study, aluminum (Al) content in soft samples is determined by LIBS and lead (Pb) content by LA-ICP-MS. The standard addition method is performed to build calibration curves for element quantification. The measurements are compared with a Hong Kong government certified acid digestion and ICP-MS procedure. The experiment is performed on standard reference materials and selected food samples. The relative errors compared with certified measurements are less than 10% for all samples, with Al content ranging from 63-1466 µg/g and Pb content from 0.37-2.35 µg/g (dry mass). Microscopy of pellets shows that laser ablation spectroscopy can be performed with 100 µg of sample (dry mass). Total analysis time from raw sample to final measurement, including preparation, is under 1 h. The results indicate that the laser ablation spectroscopy with cryogenic pelletization is a promising technique for many applications such as screening of small food samples for toxic metals and trace element analysis of millimeter biopsies.

Evaluation of Mechanical Activation and Chemical Synthesis for Particle Size Modification of White Mineral Trioxide Aggregate.

Objective: Initial setting time is one of the most important properties of calcium silicate cements (CSCs) such as white mineral trioxide aggregate (WMTA). This study aimed to evaluate the effect of two methods used to reduce the particle size of WMTA, mechanical activation and chemical synthesis. Methods: WMTA without bismuth oxide (WMTA-B) was provided and divided into four groups (n=5) including: WMTA-B, WMTA-B+10 min milling, WMTA-B+30 min milling, and sol-gel. In groups 2 and 3, the milling was performed by using tungsten carbide balls in a ratio 1:15 (w/w) and a vibration frequency of 30 Hz together with absolute ethanol. For the fourth group, polyethylene glycol (PEG), calcium acetate (Ca(C2H3O2)2), SiO2, and aluminum oxide (Al2O3) were used for the sol-gel process. After preparation, sample powders were mixed with distilled water and placed in cylindrical molds, covered with water-moistened gauze, and incubated at 37°C for 24 hours. The Vicat needle test analyzed the initial setting time. Data were analyzed by ANOVA and Tukey tests at a significance level of P<0.05. The correlation between particle size and setting time was determined. Results: Initial setting time of the sol-gel and WMTA-B+30 min milling was significantly lower than in the other two groups (P<0.05). A significant correlation was noticed between particle size and initial setting time (P<0.05). Conclusion: Sol-gel process introduces a promising alternative strategy for the reduction of initial setting time of CSC materials. While both methods increased surface area, mechanical activation was not as successful in reducing surface area and initial setting time as effectively as the sol-gel process.

A molecular understanding of magnesium aluminium silicate - drug, drug - polymer, magnesium aluminium silicate - polymer nanocomposite complex interactions in modulating drug release: Towards zero order release.

This study reports the use of ITC in understanding the thermodynamics occurring for a controlled release system in which complexation has been exploited. In this study, a model drug, propranolol hydrochloride (PPN) was complexed with magnesium aluminium silicate (MAS) and these complexes were used in combination with polyethylene oxide (PEO) as a hydrophilic carrier at various concentrations to sustain the release of PPN. DSC, XRPD, ATR-FTIR and SEM/EDX were successfully used in characterising the produced complexes. 2D- SAXS data patterns for MAS and the produced complexes were shown to be symmetric and circular with the particles showing no preferred orientation at the nanometre scale. ITC studies showed differences between PPN adsorption onto MAS compared with PPN adsorption onto a MAS-PEO mixture. At both temperatures studied the binding affinity Ka was greater for the titration of PPN into the MAS-PEO mixture (5.37E + 04 ± 7.54E + 03 M at 25 °C and 8.63E + 04 ± 6.11E + 03 M at 37 °C), compared to the affinity obtained upon binding between PPN and MAS as previously reported suggesting a stronger binding with implications for the dissolution process. MAS-PPN complexes with the PEO polymer compacts displayed desired manufacturing and formulation properties for a formulator including, reduced plastic recovery therefore potentially reducing the risk of cracking/splitting and on tooling wear, controlled release of PPN at a significantly low (5%) polymer level as well as a zero-order release profile (case II transport) using up to 50% polymer level.

0.25 Ga Salt Deposits Preserve Signatures of Habitable Conditions and Ancient Lipids.

Polygonal features in a ∼250 million-year-old Permian evaporitic deposit were investigated for their geological and organic content to test the hypothesis that they could preserve the signature of ancient habitable conditions and biological activity. Investigations on evaporitic rock were carried out as part of the MIne Analog Research (MINAR) project at Boulby Mine, the United Kingdom. The edges of the polygons have a higher clay content and contain higher abundances of minerals such as quartz and microcline, and clays such as illite and chlorite, compared with the interior of polygons, suggesting that the edges were preferred locations for the accumulation of weathering products during their formation. The mineral content and its strontium isotope ratio suggest that the material is from continental weathering at the borders of the Permian Zechstein Sea. The edges of the polygons contain material with mean δ13C and δ15N values of -20.8 and 5.3, respectively. Lipids, including alkanes and hopanes, were extracted from the interior and edges of the polygons, which are inferred to represent organic material entrained in the evaporites when they were formed. The presence of long-chain alkanes (C20-C35) that lack a carbon preference, low abundances of C23-C29 hopanes, and lack of marine, evaporitic, or thermal maturity indicators show that lipid biomarkers were, at least in part, potentially derived from a continental source and have not undergone significant thermal maturation since deposition. Lipid extractions using weak acids revealed significantly more lipids than those without acid, potentially indicating that encapsulation was not the only type of preservation mechanism occurring in Boulby salts. These data demonstrate the potential for ancient evaporites and their polygons to preserve information on local geological conditions, ancient habitability, and evidence of life. The data show that analogous martian evaporitic deposits are good targets for future life detection missions and the investigation of ancient martian habitability.

Chemical Speciation of Aluminum in Wine by LC-ICP-MS.

Aluminum is very common in the natural environment and in everyday human life. We are living in the "aluminum age." Its average daily intake should not exceed a few mg/day. Unfortunately, despite the growing number of alarming data about the toxicity of this element, human exposure to aluminum is constantly increasing. The toxicity and bioavailability of aluminum depends mainly on the form in which it occurs. The main variables conditioning the form are the concentration, the type, the molar ratio of aluminum to ligand, the pH value, and the temperature. This research presents a new method for speciation analysis of both inorganic and organic aluminum complexes in model solutions by LC-ICP-MS. Different solutions with variable pH values and different Al/ligand molar ratios (fluorides and several organic ligands, e.g., citrates and oxalates ions) were used. The chromatographic separation process was carried out based on isocratic and gradient elution, using a cation exchange analytical column. All determinations have been confirmed based on chemical equilibrium modeling programs. The new developed method was successfully applied for the first time in speciation analysis of real samples: white and red wine.

Phosphine detection in veterinary samples using headspace gas chromatography/tandem mass spectrometry with multiple reaction monitoring.

RATIONALE: Determination of phosphine exposure from zinc or aluminum phosphide fumigants continues to be a routine analytical requirement in veterinary forensic toxicology. There is a need for a more reliable and specific method than simple gas chromatography/mass spectrometry (GC/MS) analysis of sample solvent extracts, as GC/MS of extracts on capillary columns used for general screens involves significant interference from air peaks. METHODS: GC/MS/MS headspace analysis of acid-generated phosphine gas enabled study of the feasibility of devising multiple reaction monitoring (MRM) approaches to the determination of phosphine with greater specificity. RESULTS: Collision-induced dissociation in GC/MS/MS showed that phosphine generated m/z 34 → 31, 32 and 33 ion transitions by sequential proton release as well as minor transitions m/z 34 → 47, 34 → 63 and 63 → 31.5 by intermolecular collisions and double charging. Study of the formation of these product ions enabled development of MRM settings for a highly useful headspace method for phosphine detection. CONCLUSIONS: The method was validated over a working range of 5-100 ppm of phosphide generating phosphine gas which enabled retention of regular screen capillary columns without necessitating separation from air components. The method should have adequate sensitivity and reliability for veterinary toxicology laboratories confronting specimens from animals poisoned by crop fumigants.

Examining a synchrotron-based approach for in situ analyses of Al speciation in plant roots.

Aluminium (Al) K- and L-edge X-ray absorption near-edge structure (XANES) has been used to examine Al speciation in minerals but it remains unclear whether it is suitable for in situ analyses of Al speciation within plants. The XANES analyses for nine standard compounds and root tissues from soybean (Glycine max), buckwheat (Fagopyrum tataricum), and Arabidopsis (Arabidopsis thaliana) were conducted in situ. It was found that K-edge XANES is suitable for differentiating between tetrahedral coordination (peak of 1566 eV) and octahedral coordination (peak of 1568 to 1571 eV) Al, but not suitable for separating Al binding to some of the common physiologically relevant compounds in plant tissues. The Al L-edge XANES, which is more sensitive to changes in the chemical environment, was then examined. However, the poorer detection limit for analyses prevented differentiation of the Al forms in the plant tissues because of their comparatively low Al concentration. Where forms of Al differ markedly, K-edge analyses are likely to be of value for the examination of Al speciation in plant tissues. However, the apparent inability of Al K-edge XANES to differentiate between some of the physiologically relevant forms of Al may potentially limit its application within plant tissues, as does the poorer sensitivity at the L-edge.

Assessment of membrane bioreactor fouling with the addition of suspended aluminum nitride nanoparticles.

In this study, we assessed fouling in a membrane bioreactor (MBR) with the addition of suspended aluminum nitride (AlN) nanoparticles (NPs). Three parallel laboratory-scale submerged MBRs were operated with 0, 10, and 50 mg AlN NPs/L for over 70 days. The results showed that the addition of suspended AlN NPs did not significantly affect pollutant biodegradation; there was only a slight decrease in NH4+-N removal. Furthermore, the membrane's permeability was increased with effective fouling mitigation by the addition of a high amount of suspended AlN NPs. This was because the suspended AlN NPs decreased the content of polysaccharides in both the extracellular polymeric substances and soluble microbial products, and decreased the sludge floc size. However, the AlN NPs also promoted pore-blocking, particularly standard blocking, which enhanced irreversible fouling. Additionally, owing to the larger ionic radius and higher electronegativity, the AlN NPs inhibited the accumulation of framework components (SiO2). Therefore, suspended AlN NPs resulted in a thinner cake layer.

Total Recoverable Aluminum: Not Totally Relevant for Water Quality Standards.

A large water quality data set, representing more than 100 surface-water locations sampled from 2007 to 2017 in the Los Alamos area of New Mexico, USA's Pajarito Plateau, was assembled to evaluate Al concentrations in unfiltered and filtered samples. Aluminum concentrations often exceeded United States Environmental Protection Agency (USEPA) and New Mexico ambient water quality criteria (AWQC), regardless of filter size and sample location. However, AWQC are based on laboratory toxicity studies using soluble Al salts and do not reflect natural conditions in Pajarito Plateau surface waters. The plateau is predominately covered by glassy and recrystallized volcanic ashes (e.g., Bandelier Tuff) containing colloidal to sand-sized aluminosilicates. Samples from natural background drainages and areas downstream of developed regions exhibited similar Al concentrations, suggesting that AWQC exceedances are caused by naturally elevated Al concentrations. Solubility calculations indicated that most samples were oversaturated with respect to amorphous Al(OH)3 (s). Therefore, AWQC exceedances are likely artifacts of the "total recoverable" sample preparation, which includes acidification and partial digestion, thereby liberating nonbioavailable Al from aluminosilicates. Accordingly, Al concentrations were strongly associated with suspended sediment concentrations (SSCs), implying that aluminosilicates in suspended sediment contributed to AWQC exceedances and Al oversaturation. Solid-phase particle characterization, using X-ray diffraction (XRD) and scanning electron microscopy with electron dispersive spectroscopy (SEM/EDS) did not identify potentially bioavailable amorphous Al(OH)3 (s) in any sample tested. Thus, current sample collection and analysis protocols should not be used to evaluate attainment of Al AWQC on the Pajarito Plateau or locations where aluminosilicates are substantial contributors to total recoverable Al. A sample preparation method (e.g., pH 4 extraction) capable of differentiating nonbioavailable and bioavailable forms of Al is recommended. Otherwise, current New Mexico and USEPA sample preparation approaches will continue to generate artifactual AWQC exceedances in surface waters that contain aluminosilicates. Integr Environ Assess Manag 2019;00:1-14. © 2019 SETAC.

Distribution and phytotoxicity of soil labile aluminum fractions and aluminum species in soil water extracts and their effects on tall fescue.

Soil acidification can alter the biogeochemistry of ecosystems and adversely affect biota; however, there are still many debates about the toxicity of aluminum (Al) fractions and Al species in soil:water extracts to plants. In this study, five crude soils with different pH values (4.92-8.51) were collected, seeded with tall fescue and grown in rhizosphere boxes for 120 days. Then, soil properties, labile Al fractions and Al species in soil:water extracts were determined, and their toxicities to plants were analyzed. Our study showed that a stable exchangeable Al fraction (ExAl) pool exists and is supplied by other labile Al fractions. Dissolution of Al from adsorbed hydroxyl-Al fraction (HyAl) and organic-Al fraction (OrAl) may play important roles in soil Al toxicity, as HyAl and OrAl account for major parts of soil labile Al. Additionally, Al3+ and mononuclear hydroxyl-Al species in soil:water extracts have few effects to plants. Nevertheless, high negative correlations were found between Al-F- complexes and tall fescue biomass, indicating their toxicity in the natural soil environment. Thus, in many cases, Al3+ toxicity should not be emphasized because of its lower activity in soil water extracts. Moreover, toxicities of AlF3(aq) and AlF4- to plants should be emphasized, because they have been confirmed in soil water extracts in this study.

A paper platform for colorimetric determination of aluminum hydrochloride in antiperspirant samples.

A simple, fast, low-cost, portable, and eco-friendly method using a spot test on a paper platform, together with diffuse reflectance spectroscopy, was developed and validated for the quantification of aluminum hydrochloride, a potential neurotoxic agent, in antiperspirant samples. The determination of aluminum hydrochloride was performed at a wavelength of 615 nm, by measuring consumption of the purple colorimetric reagent Alizarin S, due to reaction with aluminum. The linear range was from 10.0 to 125.0 mg L-1 and could be described by the equation: AR = 0.4479 - 0.002543 CAl (R = 0.999). The limits of detection (LOD) and quantification (LOQ) were 3.06 and 10.2 mg L-1, respectively. The method was specific, accurate, and repeatable, with relative standard deviation (RSD) <5.0%. The recovery was between 92.2 and 103.4%. The method was successfully used for the determination of aluminum hydrochloride in commercial antiperspirant samples, revealing concentrations below the maximum permitted by current legislation.

27Al and 31P NMR spectroscopy method development to quantify aluminum phosphate in adjuvanted vaccine formulations.

A novel qNMR method is described for the quantitative determination of total aluminum and phosphate in aluminum phosphate (AlPO4) adjuvanted vaccine samples using solution 27Al and 31P nuclear magnetic resonance (NMR) spectroscopy. External standard calibrations of AlPO4 solutions established excellent linearity in the range of 15-40 × 10-3 M and additional studies determined the level of detection for both nuclei. A commercialized combination vaccine product (Quadracel®), along with several individual adsorbed antigen components used in the vaccine were employed as model systems for method development. The developed method is also capable of quantitating the free phosphate (i.e. the fraction not bound to AlPO4 particles) in adjuvanted vaccines. This study is the first demonstration of a solution NMR method that is suitable for measuring total aluminum, and free and total phosphate concentrations in vaccine formulations consisting of antigen(s) adsorbed to aluminum adjuvant, in a single analytical workflow.

Characterization of drilling waste from shale gas exploration in Central and Eastern Poland.

The purpose of this research was to determine and evaluate the chemical properties of drilling waste from five well sites in Central and Eastern Poland. It was found that spent drilling fluids can contain high values of nickel and mercury (270 and 8.77 mg kg-1, respectively) and can exceed the maximum permissible limits recommended by the EC regulations for safety of soils (75 mg kg-1 for nickel and 1.5 mg kg-1 for mercury). The heavy metal concentrations in the studied drill cuttings did not exceed the maximum permissible limits recommended by the EC regulation. Drilling wastes contain macroelements (e.g., calcium, magnesium, and potassium) as well as trace elements (e.g., copper, iron, zinc, and manganese) that are essential for the plant growth. It was stated that water extracts of drilling fluids and drill cuttings, according to anions presence, had not any specific constituents of concern based on FAO irrigation guidelines, the USEPA WQC, and toxicity values. X-ray diffraction analysis was used to understand the structure and texture of waste drilling fluid solids and drill cuttings. Analysis of the mineralogical character of drilling fluid solids revealed that they contained calcite, quartz, muscovite, sylvite, barite, dolomite, and orthoclase. Drill cuttings contained calcite quartz, muscovite, barite, dolomite, and barium chloride.

Systemic bone marker expression induced by grey and white mineral trioxide aggregate in normal and diabetic conditions.

AIM: To investigate the relationship between diabetes mellitus and local/systemic effects of both grey and white mineral trioxide aggregate (MTA) Angelus on bone marker expression. METHODOLOGY: Wistar rats were divided into two groups: healthy and diabetic (Alloxan induced), which were further divided into three subgroups (control, GMTA Angelus and WMTA Angelus). Polyethylene tubes filled with MTA materials or empty tubes were implanted in dorsal connective tissue. On days 7 and 30, blood samples were collected for calcium, phosphorus and ALP measurement. The animals were euthanized; implanted tubes were removed and processed for immunohistochemical analysis of osteocalcin (OCN) and osteopontin (OPN). Kruskal-Wallis followed by Dunn's multiple comparison test was performed for nonparametric data, and anova followed by Tukey's test for parametric data. RESULTS: No difference in systemic serum calcium levels between both groups was observed. On day 7, serum phosphorus levels within the WMTA healthy group were higher than that of the diabetic group. On day 30, healthy rats exhibited lower phosphorus levels than diabetic ones. At both time points, the diabetic group was associated with more ALP activity than the healthy group. Immunohistochemical analyses of the healthy group revealed OCN- and OPN-positive cells in the presence of both MTA materials. However, under diabetic conditions, both OCN and OPN were absent. CONCLUSION: Both MTA materials were associated with an increase in serum calcium, phosphorus and ALP, suggesting a potential systemic effect, along with triggered differentiation of OCN- and OPN-positive cells. Moreover, in diabetic conditions, an inhibitory effect on MTA-induced differentiation of OCN- and OPN-positive cells was detected.

Utilization of calcium-based and aluminum-based materials for the treatment of stabilized landfill leachate: a comparative study.

This study explored the efficiencies and mechanisms of refractory organic matters removal in the stabilized landfill leachate by adding different reagents. Calcium-based and aluminum-based materials were added into the leachate as comparing experiments. XRD, FTIR, and EEM were adopted to analyze the solid products and leachate. As a result, the in situ synthesized CaAl-LDHs were more beneficial for refractory organic matters removal, especially for benzodiazepines. When CaAl-LDHs were formed, the removal efficiencies of COD, UV254, and TOC were best and achieved 58.48, 81.22, and 71.30%, respectively. For fluorescent substances, humic acid-like and fulvic acid-like compounds were efficiently removed by CaAl-LDHs. In particular, CaAl-LDHs had selective removal effects on fulvic acid-like compounds, which were characteristic of small molecular weight and major carboxyl groups.

Phenolic alkaloid oleracein E attenuates oxidative stress and neurotoxicity in AlCl3-treated mice.

AIMS: Chelation therapy and antioxidant supplements have been demonstrated to be useful in ameliorating aluminum (Al) induced neurotoxicity. Oleracein E (OE) is a phenolic antioxidant alkaloid which possesses a rare tetrahydroisoquinoline/pyrrolidone tricyclic skeleton and a catechol moiety. The aim of this study was to investigate whether OE can chelate with Al and alleviate AlCl3-induced oxidative stress and neurotoxicity. MAIN METHODS: Kunming mice were administered AlCl3 (40mg/kg/d, i.p., 28days), with co-administration of OE (3mg/kg/d, 15mg/kg/d, i.g.) and the positive control piracetam (PA, 400mg/kg/d, i.g.). The Al contents in the brain and plasma were determined using ICP-MS. Al chelating ability of OE was assayed using UV spectroscopy. MDA, GSH, SOD or CAT, in the brain or plasma were determined. HE staining was used to examine hippocampal morphology alterations. IHC staining was employed to measure the expression of apoptotic-related proteins Bax, Bcl-2 and Caspase-3. KEY FINDINGS: AlCl3 remarkably increased the brain and plasma Al contents, increased lipid peroxidation and induced hippocampal neuronal damage. OE chelated with Al to form a stable complex. An increase in brain Al content by OE (15mg/kg) likely occurred through chelating with Al, which reduced the toxicity of free Al ion in the brain. OE significantly decreased MDA by regulating some antioxidant biomarkers. Furthermore, OE significantly ameliorated the protein expression changes in some apoptotic indices induced by AlCl3. SIGNIFICANCE: The phenolic alkaloid OE, as an antioxidant, Al chelator and apoptosis inhibitor, alleviates oxidative stress and neurotoxicity induced by AlCl3.

A note on unusual Si/Al ratios in PM10 and PM2.5 road dust at several locations in India.

The Si/Al ratios in road dust (PM10 and/or PM2.5) at several locations in India were examined and found to range between 1.6 and 84.9. The potential factors for this wide range of unusual Si/Al ratios in road dust are not known at this time. In addition to re-assessing data quality, the observations suggest the need to carefully quantify anthropogenic inputs of these elements to road dust. The findings of this study also contradict popular assumptions about minimal enrichment of crustal elements by anthropogenic sources and highlight the need to re-visit dust mass estimation using Si and Al as a surrogate. Further, characterization of Si/Al ratio in road dust at locations in India and the influence of local geology/geochemistry on it are especially important, if this ratio is to be used either for dust estimation or as an input to ambient aerosol mass source apportionment models.