In-conduit capture of sub-micron volcanic ash particles via turbophoresis and sintering.

Ash emission in explosive silicic eruptions can have widespread impacts for human health, agriculture, infrastructure, and aviation. Estimates of the total grainsize distribution (TGSD) generated during explosive magma fragmentation underpins eruption models and ash dispersal forecasts. Conventionally, the TGSD constrained via erupted deposits is assumed to match the TGSD produced at explosive fragmentation. Here we present observations from within the vent of a recent rhyolitic eruption (Cordón Caulle, Chile, 2011-2012), demonstrating that fine (<63 µm diameter) and ultra-fine (<2.5 µm diameter) ash particles are captured and sintered to fracture surfaces, and thus sequestered in the shallow subsurface, rather than emitted. We establish a conceptual model-uniquely contextualised through a combination of syn-eruptive observations and detailed post-eruption field investigation-in which turbophoresis (particle migration towards zones of lower turbulence) and rapid sintering create an inverse relationship between particle size and the probability of its subsurface capture. Such size-dependent capture efficiency preferentially removes submicron-diameter ash from the erupted componentry, decoupling the erupted size distribution from magmatic source conditions and potentially playing an important role in modulating eruption dynamics.

Testing behaviour and positivity for SARS-CoV-2 infection: insights from web-based participatory surveillance in the Netherlands.

OBJECTIVES: We aimed to identify populations at a high risk for SARS-CoV-2 infection but who are less likely to present for testing, by determining which sociodemographic and household factors are associated with a lower propensity to be tested and, if tested, with a higher risk of a positive test result. DESIGN AND SETTING: Internet-based participatory surveillance data from the general population of the Netherlands. PARTICIPANTS: Weekly survey data collected over a 5-month period (17 November 2020 to 18 April 2021) from a total of 12 026 participants who had contributed at least 2 weekly surveys was analysed. METHODS: Multivariable analyses using generalised estimating equations for binomial outcomes were conducted to estimate the adjusted ORs of testing and of test positivity associated with participant and household characteristics. RESULTS: Male sex (adjusted OR for testing (ORt): 0.92; adjusted OR for positivity (ORp): 1.30, age groups<20 (ORt: 0.89; ORp: 1.27), 50-64 years (ORt: 0.94; ORp: 1.06) and 65+ years (ORt: 0.78; ORp: 1.24), diabetics (ORt: 0.97; ORp: 1.06) and sales/administrative employees (ORt: 0.93; ORp: 1.90) were distinguished as lower test propensity/higher test positivity factors. CONCLUSIONS: The factors identified using this approach can help identify potential target groups for improving communication and encouraging testing among those with symptoms, and thus increase the effectiveness of testing, which is essential for the response to the COVID-19 pandemic and for public health strategies in the longer term.

A theoretical model of Surtseyan bomb fragmentation.

Surtseyan eruptions are an important class of mostly basaltic volcanic eruptions first identified in the 1960s, where erupting magma at an air-water interface interacts with large quantities of slurry, a mixture of previously ejected tephra that re-enters the crater together with water. During a Surtseyan eruption, hot magma bombs are ejected that initially contain pockets of slurry. Despite the formation of steam and anticipated subsequent high pressures inside these bombs, many survive to land without exploding. We seek to explain this by building and solving a simplified spherical mathematical model that describes the coupled evolution of pressure and temperature due to the flashing of liquid to vapour within a Surtseyan bomb while it is in flight. Analysis of the model provides a criterion for fragmentation of the bomb due to steam pressure build-up, and predicts that if diffusive steam flow through the porous bomb is sufficiently rapid the bomb will survive the flight intact. This criterion explicitly relates fragmentation to bomb properties, and describes how a Surtseyan bomb can survive in flight despite containing flashing liquid water, contributing to an ongoing discussion in volcanology about the origins of the inclusions found inside bombs.

Aerial strategies advance volcanic gas measurements at inaccessible, strongly degassing volcanoes.

Volcanic emissions are a critical pathway in Earth's carbon cycle. Here, we show that aerial measurements of volcanic gases using unoccupied aerial systems (UAS) transform our ability to measure and monitor plumes remotely and to constrain global volatile fluxes from volcanoes. Combining multi-scale measurements from ground-based remote sensing, long-range aerial sampling, and satellites, we present comprehensive gas fluxes-3760 ± [600, 310] tons day-1 CO2 and 5150 ± [730, 340] tons day-1 SO2-for a strong yet previously uncharacterized volcanic emitter: Manam, Papua New Guinea. The CO2/ST ratio of 1.07 ± 0.06 suggests a modest slab sediment contribution to the sub-arc mantle. We find that aerial strategies reduce uncertainties associated with ground-based remote sensing of SO2 flux and enable near-real-time measurements of plume chemistry and carbon isotope composition. Our data emphasize the need to account for time averaging of temporal variability in volcanic gas emissions in global flux estimates.

Ecological momentary assessment study of exposure to radiofrequency electromagnetic fields and non-specific physical symptoms with self-declared electrosensitives.

The main objective of the study is to determine if non-specific physical symptoms (NSPS) in people with self-declared sensitivity to radiofrequency electromagnetic fields (RF EMF) can be explained (across subjects) by exposure to RF EMF. Furthermore, we pioneered whether analysis at the individual level or at the group level may lead to different conclusions. By our knowledge, this is the first longitudinal study exploring the data at the individual level. A group of 57 participants was equipped with a measurement set for five consecutive days. The measurement set consisted of a body worn exposimeter measuring the radiofrequency electromagnetic field in twelve frequency bands used for communication, a GPS logger, and an electronic diary giving cues at random intervals within a two to three hour interval. At every cue, a questionnaire on the most important health complaint and nine NSPS had to be filled out. We analysed the (time-lagged) associations between RF-EMF exposure in the included frequency bands and the total number of NSPS and self-rated severity of the most important health complaint. The manifestation of NSPS was studied during two different time lags - 0-1 h, and 1-4 h - after exposure and for different exposure metrics of RF EMF. The exposure was characterised by exposure metrics describing the central tendency and the intermittency of the signal, i.e. the time-weighted average exposure, the time above an exposure level or the rate of change metric. At group level, there was no statistically significant and relevant (fixed effect) association between the measured personal exposure to RF EMF and NSPS. At individual level, after correction for multiple testing and confounding, we found significant within-person associations between WiFi (the self-declared most important source) exposure metrics and the total NSPS score and severity of the most important complaint in one participant. However, it cannot be ruled out that this association is explained by residual confounding due to imperfect control for location or activities. Therefore, the outcomes have to be regarded very prudently. The significant associations were found for the short and the long time lag, but not always concurrently, so both provide complementary information. We also conclude that analyses at the individual level can lead to different findings when compared to an analysis at group level.

Magmatic gas percolation through the old lava dome of El Misti volcano.

The proximity of the major city of Arequipa to El Misti has focused attention on the hazards posed by the active volcano. Since its last major eruption in the fifteenth century, El Misti has experienced a series of modest phreatic eruptions and fluctuating fumarolic activity. Here, we present the first measurements of the compositions of gas emitted from the lava dome in the summit crater. The gas composition is found to be fairly dry with a H2O/SO2 molar ratio of 32 ± 3, a CO2/SO2 molar ratio of 2.7 ± 0.2, a H2S/SO2 molar ratio of 0.23 ± 0.02 and a H2/SO2 molar ratio of 0.012 ± 0.002. This magmatic gas signature with minimal evidence of hydrothermal or wall rock interaction points to a shallow magma source that is efficiently outgassing through a permeable conduit and lava dome. Field and satellite observations show no evolution of the lava dome over the last decade, indicating sustained outgassing through an established fracture network. This stability could be disrupted if dome permeability were to be reduced by annealing or occlusion of outgassing pathways. Continued monitoring of gas composition and flux at El Misti will be essential to determine the evolution of hazard potential at this dangerous volcano.

Rapid laccolith intrusion driven by explosive volcanic eruption.

Magmatic intrusions and volcanic eruptions are intimately related phenomena. Shallow magma intrusion builds subsurface reservoirs that are drained by volcanic eruptions. Thus, the long-held view is that intrusions must precede and feed eruptions. Here we show that explosive eruptions can also cause magma intrusion. We provide an account of a rapidly emplaced laccolith during the 2011 rhyolite eruption of Cordón Caulle, Chile. Remote sensing indicates that an intrusion began after eruption onset and caused severe (>200 m) uplift over 1 month. Digital terrain models resolve a laccolith-shaped body ∼0.8 km3. Deformation and conduit flow models indicate laccolith depths of only ∼20-200 m and overpressures (∼1-10 MPa) that likely stemmed from conduit blockage. Our results show that explosive eruptions may rapidly force significant quantities of magma in the crust to build laccoliths. These iconic intrusions can thus be interpreted as eruptive features that pose unique and previously unrecognized volcanic hazards.

The Surtsey Magma Series.

The volcanic island of Surtsey (Vestmannaeyjar, Iceland) is the product of a 3.5-year-long eruption that began in November 1963. Observations of magma-water interaction during pyroclastic episodes made Surtsey the type example of shallow-to-emergent phreatomagmatic eruptions. Here, in part to mark the 50(th) anniversary of this canonical eruption, we present previously unpublished major-element whole-rock compositions, and new major and trace-element compositions of sideromelane glasses in tephra collected by observers and retrieved from the 1979 drill core. Compositions became progressively more primitive as the eruption progressed, with abrupt changes corresponding to shifts between the eruption's four edifices. Trace-element ratios indicate that the chemical variation is best explained by mixing of different proportions of depleted ridge-like basalt, with ponded, enriched alkalic basalt similar to that of Iceland's Eastern Volcanic Zone; however, the systematic offset of Surtsey compositions to lower Nb/Zr than other Vestmannaeyjar lavas indicates that these mixing end members are as-yet poorly contained by compositions in the literature. As the southwestern-most volcano in the Vestmannaeyjar, the geochemistry of the Surtsey Magma Series exemplifies processes occurring within ephemeral magma bodies on the extreme leading edge of a propagating off-axis rift in the vicinity of the Iceland plume.

Performance of blood glucose meters in compliance with current and future clinical ISO15197 accuracy criteria.

Since 2003, blood glucose meters for patient self testing are approved in Europe based on the accuracy performance criteria as defined by the ISO15197 guideline. A new draft ISO guideline is currently under regulatory review, which suggests more strict accuracy acceptance criteria, and which may not be entirely fulfilled by currently commercialized blood glucose meter systems. In order to investigate the compliance of BG*Star and iBG*Star and several other blood glucose meters with the new draft ISO guideline, we performed a post-hoc analysis of data obtained from a recently performed ISO-conforming clinical accuracy performance study. This study was performed with 106 patients, clinically presenting with blood glucose levels distributed over the entire measurement range and in line with the glucose distribution requirements as demanded by the guideline. The YSI 2300 STAT Plus analyzer (glucose oxidase) served as reference method. While all tested meters had been in a high degree of compliance with the current ISO criteria, performance was lower when analyzed in accordance with the new acceptance criteria (95% of readings have to be within ±15 mg/dL for values <100 mg/dL, and within ±15% for values ≥100 mg/dL). The following meters met the new criteria: Accu-Chek Aviva (95.5%/98.6%), BG*Star (98.5%/97.3%), iBG*Star (98.5%/97.3%), FreeStyle Freedom Lite (95.5%/96.6%), and OneTouch Ultra2 (95.5%/96.5%). One meter failed with low blood glucose values (Contour: 90.9%/95.9%). In conclusion, BG*Star and iBG*Star and several other branded meters met the new draft ISO15197 acceptance criteria, when tested in accordance with the instructions for use and with the ISO accuracy testing protocol in a clinical setting.

Exceptional mobility of an advancing rhyolitic obsidian flow at Cordón Caulle volcano in Chile.

The emplacement mechanisms of rhyolitic lava flows are enigmatic and, despite high lava viscosities and low inferred effusion rates, can result in remarkably, laterally extensive (>30 km) flow fields. Here we present the first observations of an active, extensive rhyolitic lava flow field from the 2011-2012 eruption at Cordón Caulle, Chile. We combine high-resolution four-dimensional flow front models, created using automated photo reconstruction techniques, with sequential satellite imagery. Late-stage evolution greatly extended the compound lava flow field, with localized extrusion from stalled, ~35 m-thick flow margins creating >80 breakout lobes. In January 2013, flow front advance continued ~3.6 km from the vent, despite detectable lava supply ceasing 6-8 months earlier. This illustrates how efficient thermal insulation by the lava carapace promotes prolonged within-flow horizontal lava transport, boosting the extent of the flow. The unexpected similarities with compound basaltic lava flow fields point towards a unifying model of lava emplacement.

Design of an ecological momentary assessment study of exposure to radiofrequency electromagnetic fields and non-specific physical symptoms.

INTRODUCTION: Idiopathic Environmental Intolerance (IEI) attributed to electromagnetic fields (EMF) refers to self-reported sensitivity mainly characterised by the attribution of non-specific physical symptoms to low-level EMF exposure emitted from sources such as mobile phones. Scientific studies have not provided evidence for the existence of IEI-EMF, but these studies did not resemble the real-life situation or suffered from poor exposure characterisation and biased recall of health symptoms. To improve existing methods for the study of IEI-EMF, an Ecological Momentary Assessment (EMA) study is designed. METHODS AND ANALYSIS: The study is an EMA study in which respondents carry personal exposure metres (exposimeters) that measure radiofrequency (RF) EMF, with frequent assessment of health symptoms and perceived EMF exposure through electronic diary registration during five consecutive days. Participants will be a selection from an epidemiological study who report to be sensitive to RF EMF. The exposimeters measure electric field strength in 12 frequency bands. Diary questions include the occurrence and severity of 10 non-specific physical symptoms, mood states and perceived exposure to (sources of) EMF. The relationship of actual and perceived EMF exposure and mood with non-specific physical symptoms will be analysed using multilevel regression analysis with time-shift models. DISCUSSION: The study has several advantages over previous studies, including assessment of personal EMF exposure and non-specific physical symptoms by an ecological method with a minimised chance of recall bias. The within-person design reduces confounding by time-stable factors (eg, personal characteristics). In the conduct of the study and the analysis and interpretation of its outcomes, some methodological issues including a high participant burden, reactivity, compliance to the study protocol and the potential of chance findings due to multiple statistical testing will be accounted for and limited as much as possible.

Effects of hospital delivery during off-hours on perinatal outcome in several subgroups: a retrospective cohort study.

BACKGROUND: Studies have demonstrated a higher risk of adverse outcomes among infants born or admitted during off-hours, as compared to office hours, leading to questions about quality of care provide during off-hours (weekend, evening or night). We aim to determine the relationship between off-hours delivery and adverse perinatal outcomes for subgroups of hospital births. METHODS: This retrospective cohort study was based on data from the Netherlands Perinatal Registry, a countrywide registry that covers 99% of all hospital births in the Netherlands. Data of 449,714 infants, born at 28 completed weeks or later, in the period 2003 through 2007 were used. Infants with a high a priori risk of morbidity or mortality were excluded. Outcome measures were intrapartum and early neonatal mortality, a low Apgar score (5 minute score of 0-6), and a composite adverse perinatal outcome measure (mortality, low Apgar score, severe birth trauma, admission to a neonatal intensive care unit). RESULTS: Evening and night-time deliveries that involved induction or augmentation of labour, or an emergency caesarean section, were associated with an increased risk of an adverse perinatal outcome when compared to similar daytime deliveries. Weekend deliveries were not associated with an increased risk when compared to weekday deliveries. It was estimated that each year, between 126 and 141 cases with an adverse perinatal outcomes could be attributed to this evening and night effect. Of these, 21 (15-16%) are intrapartum or early neonatal death. Among the 3100 infants in the study population who experience an adverse outcome each year, death accounted for only 5% (165) of these outcomes. CONCLUSION: This study shows that for infants whose mothers require obstetric interventions during labour and delivery, birth in the evening or at night, are at an increased risk of an adverse perinatal outcomes.

Self-assessment and objective determination of dexterity in patients with type 1 or type 2 diabetes mellitus.

OBJECTIVE: Insulin-treated patients perform complex treatment activities during daily routine, such as blood glucose measurements and insulin injections. We aimed to identify suitable dexterity and cognitive function tests for diabetes patients, and to compare the patient self-assessment of their dexterity skills with the test results (Jebsen-Taylor hand function test, (JHFT), motoric performance test (MLS), number connection test). METHOD: We enrolled 90 diabetes patients (36 females, 54 males): 15 type 1 with clinically suspected dexterity impairment (A: age: 60 ± 9 years), 30 type 2 with clinically suspected dexterity impairment (B: 61 ± 10 years), 30 type 1 or type 2 patients with visual impairment (C: 64 ± 6 years), and 15 type 1 or type 2 patients without obvious impairment (control group: D: 64 ± 5 years). RESULTS: There were no differences regarding neuropathy and slight impairments in the number connection test in all groups. Patient self-assessment revealed that 33.4% in group A, 33.3% in group B, 36.7% in group C and 13.7% in group D, considered themselves to have dexterity impairment. However in the JHFT test, all patients from A (100%) and B (100%), 33% from C, and 0% from D presented with dexterity impairment by only passing less than four subtests. CONCLUSIONS: Impairment of dexterity was much more frequent than believed by the patients themselves. It may be worthwhile to consider these findings when classifying patients regarding their capabilities to perform certain treatments or when assessing diabetes technology with human subjects.

BpiB05, a novel metagenome-derived hydrolase acting on N-acylhomoserine lactones.

The N-acyl-homoserine lactones (N-AHLs) play an important role in bacterial cell-cell signaling. Up to date, however, only a few different experimentally proven classes of N-AHL ring-cleaving enzymes are known. Here we report on the isolation and biochemical characterization of a novel hydrolase derived from the soil metagenome and acting on N-AHLs. The identified protein designated BpiB05 is weakly similar to hypothetical proteins from Bacteroides fragilis, the draft genomes of two Burkholderia species as well as a marine metagenomic ORF but is otherwise not similar to any known protein. BpiB05 was overexpressed in Escherichia coli as a 10× His-tagged fusion protein. The recombinant protein revealed a molecular weight of about 70kDa and was tested for its quorum quenching (QQ) activities using a lacZ-bioassay. Additional HPLC-MS analyses confirmed the lactonolytic activity of the purified protein in the presence of Ca²âº. Further tests suggested that BpiB05 strongly reduces motility in Pseudomonas aeruginosa, pyocyanin synthesis and biofilm formation in this microbe. Because BpiB05 is not distantly related to any of the currently known hydrolases it forms probably a novel group within the growing number of proteins acting on N-AHLs.

Predicting the risk of newborn children to become overweight later in childhood: the PIAMA birth cohort study.

OBJECTIVE: To develop a decision rule by which children with a high risk to develop overweight can be distinguished at birth from children at low risk. DESIGN, SETTING AND PARTICIPANTS: Data of 1 687 Dutch children born in 1996/1997 who participated in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) longitudinal birth cohort study were analysed. Perinatal candidate predictors of overweight at 8 years of age were selected and a prediction model was developed using stepwise model selection based on the Akaike Information Criterion (AIC). The prediction model was internally validated using resampling techniques. Outcome measure. Overweight at the age of 8 years. RESULTS: A total of 13.9% (n = 253) of the children were overweight at 8 years of age. Independent positive predictors of overweight were paternal and maternal body mass index, female gender, smoking in the parental house, birth weight and hospital delivery. From the model, a decision rule was derived by which an overweight score could be calculated. Of the children with an overweight score below 89.45, only 2.7% were overweight at the age of 8, whereas in children with an overweight score above 105.02 the prevalence of overweight was 35.4%. CONCLUSION: The risk of overweight at the age of 8 years can be predicted with six characteristics that are available at birth. The decision rule developed in this study may help to target early preventive measures against overweight in high-risk children.

Application of bioassays in toxicological hazard, risk and impact assessments of dredged sediments.

Given the potential environmental consequences of dumped dredged harbour sediments it is vital to establish the potential risks from exposure before disposal at sea. Currently, European legislation for disposal of contaminated sediments at sea is based on chemical analysis of a limited number of well-known contaminants for which maximum acceptable concentrations, action levels (ALs), have been set. The present paper addresses the issue of the applicability of in vitro and in vivo bioassays for hazard, risk and local impact assessment of dredged polluted sediments to be disposed of at sea. It discusses how and to what extent selected bioassays can fill in the gaps left open by chemical analysis and the way in which the bioassays may contribute to the present licensing system for disposal. Three different purposes for application were distinguished: the most basic application (A) is a rapid determination of the hazard (potential toxicity) of dredged sediments which is then compared to ALs in a licensing system. As with chemical analysis on whole sediment extracts, the bioavailability of the chemicals is not taken into account. As in vitro assays with sediment extracts are not sensitive to matrix effects, a selection of specific in vitro bioassays can be suitable fast and standardized additions for the licensing system. When the outcome of (A) does not convincingly demonstrate whether the sediment is clean enough or too polluted, further bioanalysis can help the decision making process (B). More aspects of the mostly unknown complex chemical mixtures are taken into account, including the bioavailability and chronic toxicity focusing on ecologically relevant endpoints. The ecotoxicological pressure imposed by the dredged sediments can be quantified as the potentially affected fraction (PAF) based on chemical or biological analysis of levels of contaminants in sediment or biota. To validate the predicted risk, the actual impact of dumped harbour sediments on local ecosystems (C) can be determined using a dedicated set of in vitro and in vivo bioassays as well as bio-indicators selected based on the information obtained from (A) and (B) and on the characteristics of the local ecosystem. Conversely, the local sediment impact assessment (C) can direct fine-tuning of the selection of chemical and bioassay analyses and for setting safe levels in the licensing system. It is concluded that in vitro and in vivo bioassays and biological indicators are useful tools in the process of hazard, ecotoxicological risk and impact assessment of dredged harbour sediments, provided they are consciously chosen and quality criteria for assay performance are defined.

Prediction of the ease of subdivision of scored tablets from their physical parameters.

At present, the ease of subdivision of scored tablets is estimated in vivo. In order to replace such in vivo testing and to develop a surrogate test which uses in vitro techniques, the association between physical parameters of scored tablets and their ease of subdivision was studied. The physical properties of 23 brands of scored tablets of which their ease of subdivision in vivo was known were established. Statistical modeling using a logistic regression model was used to fit the data and estimate the contribution of each physical parameter to the goodness of the fit. For scored oblong tablets, the critical parameters for their ease of subdivision are: diameter; diameter/width ratio; depth of score line and resistance to crushing. Criteria for each of these parameters were derived. All criteria need to be complied with to guarantee sufficient ease of subdivision of scored oblong tablets. For scored round tablets the critical parameters, in decreasing order of importance, for their ease of subdivision, are: resistance to crushing, diameter, score mark (one- or two-sided), and shape (flat or biconvex). A five-parameter predictive model was developed, showing excellent discrimination. For development, the proposed surrogate tests are sufficiently reliable. For release testing and stability studies, resistance to crushing of a scored tablet is a reliable predictor of its ease of subdivision.

Relationship between costs of lifestyle interventions and weight loss in overweight adults.

Lifestyle interventions in a healthcare setting are effective for weight loss, but it is unclear whether more expensive interventions result in more weight loss. Our objective was to explore the relationship between intervention costs and effectiveness in a systematic review of randomized trials. Intervention studies were selected from 14 reviews and from a systematic MEDLINE-search. Studies had to contain a dietary and a physical activity component and report data on measured weight loss in healthy Caucasian overweight adults. Intervention costs were calculated in a standardized way. The association between costs and percentage weight loss after 1 year was assessed using regression analysis. Nineteen original studies describing 31 interventions were selected. The relationship between weight loss and intervention costs was best described by an asymptotic regression model, which explained 47% of the variance in weight loss. A clinically relevant weight loss of 5% was already observed in interventions of approximately euro110. Results were similar in an intention-to-treat analysis. In conclusion, lifestyle interventions in health care for overweight adults are relatively cheap and higher intervention costs are associated with more weight loss, although the effect of costs on weight loss levels off with growing costs.

Predicting the long-term prognosis of children with symptoms suggestive of asthma at preschool age.

BACKGROUND: Clinicians have difficulty in diagnosing asthma in preschool children with suggestive symptoms. OBJECTIVE: We sought to develop a clinical asthma prediction score for preschool children who have asthma-like symptoms for the first time. METHODS: The Prevalence and Incidence of Asthma and Mite Allergy birth cohort followed 3,963 children for 8 years. Between 0 and 4 years of age, 2,171 (55%) children reported "wheezing," "coughing at night without a cold," or both. In these children possible predictor variables for asthma were assessed at the age respiratory symptoms were first reported. Asthma was defined as wheezing, inhaled steroid prescription, or a doctor's diagnosis of asthma at both age 7 and 8 years of age. RESULTS: Eleven percent of children with symptoms at 0 to 4 years of age had asthma at 7 to 8 years of age. Eight clinical parameters independently predicted asthma at 7 to 8 years of age: male sex, postterm delivery, parental education and inhaled medication, wheezing frequency, wheeze/dyspnea apart from colds, respiratory infections, and eczema. In 72% of the cases, the model accurately discriminated between asthmatic and nonasthmatic children. A clinical risk score was developed (range, 0-55 points). Symptomatic children with a score of less than 10 points had a 3% risk, whereas children with a score of 30 points or greater had a 42% risk of asthma. CONCLUSION: A risk score based on 8 readily available clinical parameters at the time preschool children first reported asthma-like symptoms predicted the risk of asthma at 7 to 8 years of age.

Metagenome-derived clones encoding two novel lactonase family proteins involved in biofilm inhibition in Pseudomonas aeruginosa.

Here we report the isolation and characterization of three metagenome-derived clones that interfere with bacterial quorum sensing and degrade N-(3-oxooctanoyl)-l-homoserine lactone (3-oxo-C(8)-HSL). By using a traI-lacZ gene fusion, the metagenome-derived clones were identified from a soil DNA library and analyzed. The open reading frames linked to the 3-oxo-C(8)-HSL-degrading activities were designated bpiB01, bpiB04, and bpiB07. While the BpiB07 protein was similar to a known lactonase, no significant similarities were observed for the BpiB01 and BpiB04 proteins or the deduced amino acid sequences. High-performance liquid chromatography-mass spectrometry analyses confirmed that the identified genes encode novel lactone-hydrolyzing enzymes. The original metagenome-derived clones were expressed in Pseudomonas aeruginosa and employed in motility and biofilm assays. All clones were able to reproducibly inhibit motility in P. aeruginosa. Furthermore, these genes clearly inhibited biofilm formation in P. aeruginosa when expressed in P. aeruginosa PAO1. Thus, this is the first study in which metagenome-derived proteins have been expressed in P. aeruginosa to successfully inhibit biofilm formation.