Dissecting the respective roles of microbiota and host genetics in the susceptibility of Card9-/- mice to colitis.

BACKGROUND: The etiology of inflammatory bowel disease (IBD) is unclear but involves both genetics and environmental factors, including the gut microbiota. Indeed, exacerbated activation of the gastrointestinal immune system toward the gut microbiota occurs in genetically susceptible hosts and under the influence of the environment. For instance, a majority of IBD susceptibility loci lie within genes involved in immune responses, such as caspase recruitment domain member 9 (Card9). However, the relative impacts of genotype versus microbiota on colitis susceptibility in the context of CARD9 deficiency remain unknown. RESULTS: Card9 gene directly contributes to recovery from dextran sodium sulfate (DSS)-induced colitis by inducing the colonic expression of the cytokine IL-22 and the antimicrobial peptides Reg3ß and Reg3γ independently of the microbiota. On the other hand, Card9 is required for regulating the microbiota capacity to produce AhR ligands, which leads to the production of IL-22 in the colon, promoting recovery after colitis. In addition, cross-fostering experiments showed that 5 weeks after weaning, the microbiota transmitted from the nursing mother before weaning had a stronger impact on the tryptophan metabolism of the pups than the pups' own genotype. CONCLUSIONS: These results show the role of CARD9 and its effector IL-22 in mediating recovery from DSS-induced colitis in both microbiota-independent and microbiota-dependent manners. Card9 genotype modulates the microbiota metabolic capacity to produce AhR ligands, but this effect can be overridden by the implantation of a WT or "healthy" microbiota before weaning. It highlights the importance of the weaning reaction occurring between the immune system and microbiota for host metabolism and immune functions throughout life. A better understanding of the impact of genetics on microbiota metabolism is key to developing efficient therapeutic strategies for patients suffering from complex inflammatory disorders. Video Abstract.

Water, sanitation, and hygiene vulnerability in child stunting in developing countries: a systematic review with meta-analysis.

OBJECTIVES: This study aimed to perform a systematic review and meta-analysis to assess the scientific evidence of the relationship between vulnerability to access to safe drinking water, sanitation, and hygiene (WASH) practices on stunting in children aged <5 years in developing countries. STUDY DESIGN: This is a systematic review and meta-analysis article to assess the relationship between under-five stunting and WASH vulnerability in developing countries. METHODS: The systematic review with meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol methodology. The following databases were used: LILACS, MEDLINE (via PubMed), SciELO, Web of Science, ScienceDirect, SCOPUS, and Embase. All original studies identified that related WASH vulnerability to stunting in children aged <5 years in developing countries was included. Three authors performed independently the selection and extraction of data from the articles. The statistical software STATA version 11 was used. Cochran's Q test and Chi-square test (I2) with 95% significance were used to assess the heterogeneity of the studies. RESULTS: The search resulted in the initial identification of 2047 articles; after reading the abstracts, followed by the full articles, 14 articles were included in the systematic review and eight articles were included in the meta-analysis. The studies selected for the systematic review were published between the years 1992 and 2021 and conducted in eight countries, namely, Ethiopia, India, Indonesia, Bangladesh, Tanzania, Peru, China, and Lesotho. The studies assessed vulnerability to access to WASH on the growth of children aged <5 years. There was a significant difference when relating WASH vulnerability to children's height. The meta-analysis of this study showed that the impact of WASH on child stunting is significant when it comes to lack of sanitation in 72% of the studies. CONCLUSIONS: The study found that WASH vulnerability contributes to stunting in children aged <5 years in developing countries. Based on our findings, we recommend incorporating WASH strategies, especially sanitation, into the formulation of interventions integrating with health promotion policies for healthy early childhood development.

Toxicological evaluation of brominated vegetable oil in Sprague Dawley rats.

Brominated vegetable oil (BVO) has been approved by the US Food and Drug Administration on an interim basis as a food additive. Past studies have raised concerns about potential toxicities from consuming BVO. To investigate further these toxicities, we conducted a 90-day dietary exposure study in Sprague Dawley rats and analyzed tissue distribution of the main metabolites. Six-week-old male and female rats were fed diets containing 0 (control), 0.002%, 0.02%, 0.1%, or 0.5% BVO by weight. Statistically significant increases were observed in the serum bromide in the high-dose group of both sexes and in the incidence of thyroid follicular cell hypertrophy in the two highest dose groups of males and the high-dose group of females. An increase in serum TSH was observed in the high-dose group for both sexes, as well as a decrease in serum T4 in the high-dose males. A clear dose-response was observed in di- and tetra-bromostearic acid levels in the heart, liver, and inguinal fat. These data expand upon previous observations in rats and pigs that oral exposure to BVO is associated with increased tissue levels of inorganic and organic bromine, and that the thyroid is a potential target organ of toxicity.

Purpureocillium lilacinum an emergent pathogen: antifungal susceptibility of environmental and clinical strains.

Purpureocillium lilacinum is a filamentous and hyaline fungus cosmopolitan, saprophytic, largely used in the biological control of plant-parasitic nematodes and insects, also considered an emerging and opportunistic human pathogen. The standard treatment for hyalohyphomycosis caused by P. lilacinum is not yet defined, since this fungus is resistant to different antifungals, in vitro and in vivo. The aim of this study was to evaluate and compare in vitro antifungal activity against environmental and clinical P. lilacinum isolates and our results demonstrated that these isolates can be resistant to newer generation triazoles, such as voriconazole, and to caspofungin, a drug of the echinocandin class. In summary, we highlight the importance of knowing the different susceptibility profiles of P. lilacinum isolates, and besides that, the emergence of uncommon human and animal opportunistic fungi, such P. lilacinum, especially during COVID-19, highlight the need for antifungal susceptibility testing of isolates since empirical therapy with different treatment schedules failed in great number of patients.

r-Process elements from magnetorotational hypernovae.

Neutron-star mergers were recently confirmed as sites of rapid-neutron-capture (r-process) nucleosynthesis1-3. However, in Galactic chemical evolution models, neutron-star mergers alone cannot reproduce the observed element abundance patterns of extremely metal-poor stars, which indicates the existence of other sites of r-process nucleosynthesis4-6. These sites may be investigated by studying the element abundance patterns of chemically primitive stars in the halo of the Milky Way, because these objects retain the nucleosynthetic signatures of the earliest generation of stars7-13. Here we report the element abundance pattern of the extremely metal-poor star SMSS J200322.54-114203.3. We observe a large enhancement in r-process elements, with very low overall metallicity. The element abundance pattern is well matched by the yields of a single 25-solar-mass magnetorotational hypernova. Such a hypernova could produce not only the r-process elements, but also light elements during stellar evolution, and iron-peak elements during explosive nuclear burning. Hypernovae are often associated with long-duration γ-ray bursts in the nearby Universe8. This connection indicates that similar explosions of fast-spinning strongly magnetized stars occurred during the earliest epochs of star formation in our Galaxy.

Detecting Dissociation Dynamics of Phosphorus Molecular Ions by Atom Probe Tomography.

Dissociation processes involving phosphorus cations were investigated during laser-assisted atom probe tomography of crystalline indium phosphide (InP). This technique not only allows the formation of medium-sized phosphorus cations by means of femtosecond laser pulses under ultrahigh vacuum and high electric field conditions but also allows one to study the time-resolved dissociation dynamics. Data reveal the formation of cations up to P232+ and their subsequent dissociation into two smaller Pk+ cations (k > 2). The use of a time- and position-sensitive detector combined with numerical calculations provided information related to the molecule orientation, decay time, and kinetic energy release during dissociation phenomena. Results suggest that the dissociation processes are most likely due to the emission of Pk2+ cations in excited states and their subsequent decay in low field regions during their flight toward the detector. This study provides operative guidelines to obtain information on dissociation processes using a tomographic atom probe as a reaction microscope and indicates the current capabilities and limitations of such an approach.

A photonic atom probe coupling 3D atomic scale analysis with in situ photoluminescence spectroscopy.

Laser enhanced field evaporation of surface atoms in laser-assisted Atom Probe Tomography (APT) can simultaneously excite photoluminescence in semiconductor or insulating specimens. An atom probe equipped with appropriate focalization and collection optics has been coupled with an in situ micro-photoluminescence (µPL) bench that can be operated during APT analysis. The photonic atom probe instrument we have developed operates at frequencies up to 500 kHz and is controlled by 150 fs laser pulses tunable in energy in a large spectral range (spanning from deep UV to near IR). Micro-PL spectroscopy is performed using a 320 mm focal length spectrometer equipped with a CCD camera for time-integrated and with a streak camera for time-resolved acquisitions. An example of application of this instrument on a multi-quantum well oxide heterostructure sample illustrates the potential of this new generation of tomographic atom probes.

A two-year toxicology study of bisphenol A (BPA) in Sprague-Dawley rats: CLARITY-BPA core study results.

We report the data from the guideline-compliant two-year toxicology study conducted as part of the Consortium Linking Academic and Regulatory Insights on Bisphenol A Toxicity (CLARITY-BPA). BPA (0, 2.5, 25, 250, 2,500, and 25,000 µg/kg body weight (bw)/day) was administered daily by gavage in 0.3% carboxymethylcellulose vehicle to NCTR Sprague-Dawley rats from gestation day 6 through the start of parturition and then directly to pups from the day after birth until postnatal day 21 (stop-dose arm) or continuously until termination at one or two years. The stop-dose arm was included to assess the potential for any BPA effects that were due to developmental exposure. No BPA-related effects were evident in the in-life and non-histopathology data. Neoplastic and nonneoplastic lesions diagnosed in both females and males were common age-associated lesions that were variable across control and BPA-treated groups. The lack of consistent responses within the continuous- and stop-dose arms within and across tissues brought into question the plausible relationship of most of these lesions to BPA treatment. There was a possible relationship between the increased incidences of lesions in the female reproductive tract and the male pituitary and exposure to the 25,000 µg BPA/kg bw/day dose level.

Photoassisted and multiphoton emission from single-crystal diamond needles.

Practical realization of stable and high brightness sources of ultra-short electron pulses is an important issue in the development of time-resolved electron microscopy for the study of ultra-fast dynamics in materials. Here, we report on the experimental investigation of static (in the dark) and pulsed (under illumination by sub-picosecond laser pulses at 1040 nm) electron emission from single-crystal diamond needles. A significant increase of electron emission current was detected under laser illumination. The nonlinear dependence of the emission current on the laser intensity and on the angle between the needle and the laser beam polarization axis suggests multi-photon emission processes. This interpretation is in agreement with electron spectroscopy measurements performed for electrons emitted at different bias voltages and different laser power levels and repetition rates. The remarkable feature of the diamond emitters is their stability under high average power of laser radiation. This provides a new highly efficient source of photoemitted electrons based on single-crystal diamond.

Spatial and Compositional Biases Introduced by Position Sensitive Detection Systems in APT: A Simulation Approach.

Due to the low capacity of contemporary position-sensitive detectors in atom probe tomography (APT) to detect multiple events, material analyses that exhibit high numbers of multiple events are the most subject to compositional biases. To solve this limitation, some researchers have developed statistical correction algorithms. However, those algorithms are only efficient when one is confronted with homogeneous materials having nearly the same evaporation field between elements. Therefore, dealing with more complex materials must be accompanied by a better understanding of the signal loss mechanism during APT experiments. By modeling the evaporation mechanism and the whole APT detection system, it may be possible to predict compositional and spatial biases induced by the detection system. This paper introduces a systematic study of the impact of the APT detection system on material analysis through the development of a simulation tool.

Helicobacter pylori: qué debemos saber en el año 2018. Revisión de la evidencia y nuevas recomendaciones de tratamiento / Helicobacter pylori: what should we know in the year 2018. Review of the evidence and new treatment recommendations

Helicobacter pylori (HP) is the most widely chronic human infection around the world, and the main risk factor for the development of gastric cancer. Our country has high rates of this neoplasia and a high prevalence of HP infection. Even both have fallen in the last year, is a major concern to diagnose the population infected with HP in early stages, before the development of premalignant lesions and properly eradicate this infection. In this review, we discussed the different methods for the diagnosis of HP and factors that change positivity as the use of proton pump inhibitors. Also, we discussed the factors to be considered in the choice of the treatment, like local resistance to antibiotics, specially clarithromycin. In the last years has been documented in Chile a significant increase in resistance to clarithromycin, from 20 to 46%, which predicts inadequate effectiveness for the classic triple therapy. As the result of the previous analysis we discussed new possible therapies, including bismuth quadruple therapy and concomitant therapy. (AU)

Compositional accuracy of atom probe tomography measurements in GaN: Impact of experimental parameters and multiple evaporation events.

A systematic study of the biases occurring in the measurement of the composition of GaN by Atom Probe Tomography was carried out, in which the role of surface electric field and laser pulse intensity has been investigated. Our data confirm that the electric field is the main factor influencing the measured composition, which exhibits a deficiency of N at low field and a deficiency of Ga at high field. The deficiency of Ga at high field is interpreted in terms of preferential evaporation of Ga. The detailed analysis of multiple evaporation events reveals that the measured composition is not affected by pile-up phenomena occurring in detection system. The analysis of correlation histograms yields the signature of the production of neutral N2 due to the dissociation of GaN32+ ions. However, the amount of N2 neutral molecules that can be detected cannot account for the N deficiency found at low field. Therefore, we propose that further mechanisms of neutral N evaporation could be represented by dissociation reactions such as GaN+→ Ga++ N and GaN2+→ Ga2++ N.

La alta prevalencia de lesiones premalignas gástricas y el bajo rendimiento diagnóstico de la visión endoscópica son argumentos a favor de la toma sistemática de biopsias gástricas por Protocolo Sydney / The high prevalence of gastric premalignant lesions and the low diagnostic performance of endoscopic vision advocate towards a systematic gastric biopsy sampling using Sydney Protocol

Background: Atrophic gastritis (AG) and intestinal metaplasia (IM) are stages that appear in the process of gastric carcinogenesis. Their presence requires programmed endoscopic vigilance. Objectives: To determine the frequency of AG and IM in gastric biopsies (GB) taken according to Sydney Protocol and to correlate them with endoscopic findings. Methods: Retrospective descriptive analysis of 233 upper gastrointestinal endoscopies with GB per Sydney Protocol. OLGA (Operative Link for Gastritis Assessment) and OLGIM (Operative Link for Gastric Intestinal Metaplasia Assessment) scores were calculated based on the GB description. Endoscopic findings were analyzed for atypical findings and compared to the GB report. Statistic analysis for Kappa and ANOVA was performed via Stata 12. Results: Mean age of patients was 58 ± 12 years. 69% were women. The frequency of AG and IM was 44% and 33% in the antrum, 31% and 20% in the angular incisure and 14% and 9% in the body, respectively. AG and IM were more frequent in the antrum (p < 0.05). AG and IM were more severe in the angular incisure and body (p < 0.05). We were unable to calculate OLGA and OLGIM in 6% and 9% of cases, respectively, due to absence of severity description in GB. 53% were OLGA 0, 42% OLGA I-II and 5% OLGA III-IV. 70% were OLGIM 0, 25% OLGIM I-II and 5% OLGIM III-IV. Agreement between endoscopic and histological findings was best for IM in the antrum (75.5%, Kappa 0.4). Sensitivity and specificity of endoscopic findings were 39% and 70% for AG, and 30% and 85% for IM, respectively. Conclusion: AG and IM are frequent findings in our patients. Due to the low endoscopic sensitivity for AG and IM, we suggest a systematic GB sampling using Sydney Protocol in patients over 40 years old.

Introducción: La gastritis crónica atrófica (GCA) y la metaplasia intestinal (MI) son etapas en el proceso de carcinogénesis gástrica, su presencia requiere control endoscópico programado. Objetivos: Determinar la frecuencia de GCA y MI en biopsias gástricas (BG) por protocolo de Sydney y relacionarlas con el hallazgo endoscópico. Métodos: Estudio descriptivo mediante revisión de 233 endoscopias digestivas altas con BG por Protocolo Sydney. Se graduó puntaje OLGA (Operative Link for Gastritis Assessment) y OLGIM (Operative Link for Gastric Intestinal Metaplasia Assessment) según la descripción de la BG. Se definió el hallazgo endoscópico según su informe y se comparó con BG como patrón de referencia. Estadística: Stata 12 para Kappa y ANOVA. Resultados: Edad promedio 58 ± 12 años, 69% mujeres. La frecuencia de GCA y MI en antro fue de 44 y 33%, en ángulo 31 y 20% y en cuerpo 14 y 9%, respectivamente. Hubo mayor frecuencia de GCA y MI en antro (p < 0,05). La graduación de GCA y MI fue mayor en ángulo y cuerpo (p < 0,05). No se obtuvo OLGA en 6% y OLGIM en 9% por ausencia de graduación. La frecuencia de OLGA 0 fue de 53%, OLGA I-II 42%, OLGA III-IV 5%, OLGIM O 70%, OLGIM I-II 25% y OLGIM III-IV 5%. La mejor correlación se observó entre la MI antral endoscópica con la histológica (75,5%, Kappa 0,4). La sensibilidad y especificidad endoscópica fue de 39 y 70% para GCA y 30 y 85% para MI. Conclusión: GCA y MI son hallazgos frecuentes en nuestros pacientes. Por la baja sensibilidad endoscópica en la identificación de GCA y MI sugerimos la toma sistemática de BG por protocolo de Sydney en pacientes mayores de 40 años.

Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way.

The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than helium ('metals') have been found in the outer regions ('halo') of the Milky Way. The first stars and their immediate successors should, however, preferentially be found today in the central regions ('bulges') of galaxies, because they formed in the largest over-densities that grew gravitationally with time. The Milky Way bulge underwent a rapid chemical enrichment during the first 1-2 billion years, leading to a dearth of early, metal-poor stars. Here we report observations of extremely metal-poor stars in the Milky Way bulge, including one star with an iron abundance about 10,000 times lower than the solar value without noticeable carbon enhancement. We confirm that most of the metal-poor bulge stars are on tight orbits around the Galactic Centre, rather than being halo stars passing through the bulge, as expected for stars formed at redshifts greater than 15. Their chemical compositions are in general similar to typical halo stars of the same metallicity although intriguing differences exist, including lower abundances of carbon.

Evaluation of serum and liver toxicokinetics for furan and liver DNA adduct formation in male Fischer 344 rats.

Furan is a food processing contaminant found in many common cooked foods that induces liver toxicity and liver cancer in animal models treated with sufficient doses. The metabolism of furan occurs primarily in the liver where CYP 2E1 produces a highly reactive bis-electrophile, cis-2-butene-1,4-dial (BDA). BDA reacts with nucleophilic groups in amino acids and DNA in vitro to form covalent adducts. Evidence for BDA-nucleoside adduct formation in vivo is limited but important for assessing the carcinogenic hazard of dietary furan. This study used controlled dosing with furan in Fischer 344 rats to measure serum and liver toxicokinetics and the possible formation of BDA-nucleoside adducts in vivo. After gavage exposure, furan concentrations in the liver were consistently higher than those in whole blood (∼6-fold), which is consistent with portal vein delivery of a lipophilic compound into the liver. Formation of BDA-2'-deoxycytidine in furan-treated rat liver DNA was not observed using LC/MS/MS after single doses as high as 9.2 mg/kg bw or repeated dosing for up to 360 days above a consistent background level (1-2 adducts per 10(8) nucleotides). This absence of BDA-nucleoside adduct formation is consistent with the general lack of evidence for genotoxicity of furan in vivo.

[CT-scan evaluation of calvarial bone donor site reconstruction using calcium phosphate cement]. / Évaluation tomodensitométrique de la reconstruction des sites donneurs calvariaux par ciment de phosphate de calcium.

UNLABELLED: The aim of reconstructing a calvarial donor site with biomaterial is to reconstruct the skull vault. The aim of this retrospective study was to assess the quality of reconstruction of calvarial bone with Hydroset™ (Stryker™) in patients having undergone monocortical parietal bone graft harvesting. PATIENTS AND METHOD: The donor sites of patients having undergone calvarial bone harvesting had been reconstructed with Hydroset™ cement over a period of four years. Calvarial bone reconstruction and the thickness of the parietal bone were evaluated by CT scan. RESULTS: Twenty-six patients had undergone reconstruction. The CT scan revealed a good integration of Hydroset™ with maintained thickness of the biomaterial. The parietal bone thickness was increased by 0.67 mm on average (P=0.002). DISCUSSION: The reconstruction of calvarial donor site bone defect with Hydroset™, after a monocortical harvesting, demonstrates parietal osseous thickness maintained in time.

A single low-energy, iron-poor supernova as the source of metals in the star SMSS J031300.36-670839.3.

The element abundance ratios of four low-mass stars with extremely low metallicities (abundances of elements heavier than helium) indicate that the gas out of which the stars formed was enriched in each case by at most a few--and potentially only one--low-energy supernova. Such supernovae yield large quantities of light elements such as carbon but very little iron. The dominance of low-energy supernovae seems surprising, because it had been expected that the first stars were extremely massive, and that they disintegrated in pair-instability explosions that would rapidly enrich galaxies in iron. What has remained unclear is the yield of iron from the first supernovae, because hitherto no star has been unambiguously interpreted as encapsulating the yield of a single supernova. Here we report the optical spectrum of SMSS J031300.36-670839.3, which shows no evidence of iron (with an upper limit of 10(-7.1) times solar abundance). Based on a comparison of its abundance pattern with those of models, we conclude that the star was seeded with material from a single supernova with an original mass about 60 times that of the Sun (and that the supernova left behind a black hole). Taken together with the four previously mentioned low-metallicity stars, we conclude that low-energy supernovae were common in the early Universe, and that such supernovae yielded light-element enrichment with insignificant iron. Reduced stellar feedback both chemically and mechanically from low-energy supernovae would have enabled first-generation stars to form over an extended period. We speculate that such stars may perhaps have had an important role in the epoch of cosmic reionization and the chemical evolution of early galaxies.

Functional characterization of the water-soluble organic carbon of size-fractionated aerosol in the southern Mississippi Valley.

The chemical content of water-soluble organic carbon (WSOC) as a function of particle size was characterized in Little Rock, Arkansas in winter and spring 2013. The objectives of this study were to (i) compare the functional characteristics of coarse, fine and ultrafine WSOC and (ii) reconcile the sources of WSOC for periods when carbonaceous aerosol was the most abundant particulate component. The WSOC accounted for 5 % of particle mass for particles with δp > 0.96 µm and 10 % of particle mass for particles with δp < 0.96 µm. Non-exchangeable aliphatic (H-C), unsaturated aliphatic (H-C-C=), oxygenated saturated aliphatic (H-C-O), acetalic (O-CH-O) and aromatic (Ar-H) protons were determined by proton nuclear magnetic resonance (1H-NMR). The total non-exchangeable organic hydrogen concentrations varied from 4.1 ± 0.1 nmol m-3 for particles with 1.5 < δp < 3.0 µm to 73.9 ± 12.3 nmol m-3 for particles with δp < 0.49 µm. The molar H/C ratios varied from 0.48 ± 0.05 to 0.92 ± 0.09, which were comparable to those observed for combustion-related organic aerosol. The R-H was the most abundant group, representing about 45 % of measured total non-exchangeable organic hydrogen concentrations, followed by H-C-O (27 %) and H-C-C= (26 %). Levoglucosan, amines, ammonium and methanesulfonate were identified in NMR fingerprints of fine particles. Sucrose, fructose, glucose, formate and acetate were associated with coarse particles. These qualitative differences of 1H-NMR profiles for different particle sizes indicated the possible contribution of biological aerosols and a mixture of aliphatic and oxygenated compounds from biomass burning and traffic exhausts. The concurrent presence of ammonium and amines also suggested the presence of ammonium/aminium nitrate and sulfate secondary aerosol. The size-dependent origin of WSOC was further corroborated by the increasing δ13C abundance from -26.81 ± 0.18 ‰ for the smallest particles to -25.93 ± 0.31 ‰ for the largest particles and the relative distribution of the functional groups as compared to those previously observed for marine, biomass burning and secondary organic aerosol. The latter also allowed for the differentiation of urban combustion-related aerosol and biological particles. The five types of organic hydrogen accounted for the majority of WSOC for particles with δp > 3.0 µm and δp < 0.96 µm.

Soil humic-like organic compounds in prescribed fire emissions using nuclear magnetic resonance spectroscopy.

Here we present the chemical characterization of the water-soluble organic carbon fraction of atmospheric aerosol collected during a prescribed fire burn in relation to soil organic matter and biomass combustion. Using nuclear magnetic resonance spectroscopy, we observed that humic-like substances in fire emissions have been associated with soil organic matter rather than biomass. Using a chemical mass balance model, we estimated that soil organic matter may contribute up to 41% of organic hydrogen and up to 27% of water-soluble organic carbon in fire emissions. Dust particles, when mixed with fresh combustion emissions, substantially enhances the atmospheric oxidative capacity, particle formation and microphysical properties of clouds influencing the climatic responses of atmospheric aeroso. Owing to the large emissions of combustion aerosol during fires, the release of dust particles from soil surfaces that are subjected to intense heating and shear stress has, so far, been lacking.