Recombination of vibrationally cold N2+ ions with electrons.

Recombination of vibrationally cold N2+ ions with electrons was studied in the temperature range of 140-250 K. A cryogenic stationary afterglow apparatus equipped with cavity ring-down spectrometer and microwave diagnostics was utilized to probe in situ the time evolutions of number densities of particular rotational and vibrational states of N2+ ions and of electrons. The obtained value of the recombination rate coefficient for the recombination of the vibrational ground state of N2+ with electrons is αv=0 = (2.95 ± 0.50) × 10-7(300/T)(0.28±0.07) cm3 s-1, while that for the first vibrationally excited state was inferred as αv=1 = (4 ± 4) × 10-8 cm3 s-1 at 250 K.

Stationary afterglow apparatus with CRDS for study of processes in plasmas from 300 K down to 30 K.

A cryogenic stationary afterglow apparatus equipped with a near-infrared cavity-ring-down-spectrometer (Cryo-SA-CRDS) for studies of electron-ion recombination processes in the plasma at temperatures 30-300 K has been designed, constructed, tested, and put into operation. The plasma is generated in a sapphire discharge tube that is contained in a microwave cavity. The cavity and the tube are attached to the second stage of the cold head of the cryocooler system, and they are inserted to an UHV chamber with mirrors for CRDS and vacuum windows on both ends of the tube. The temperature of the discharge tube can be made as low as 25 K. In initial test measurements, the discharge was ignited in He/Ar/H2 or He/H2 gas mixtures and the density of H3+ ions and their kinetic and rotational temperatures were measured during the discharge and afterglow. From the measured decrease in the ion density, during the afterglow, effective recombination rate coefficients were determined. Plasma relaxation was studied in He/Ar gas mixtures by monitoring the presence of highly excited argon atoms. The spectroscopic measurements demonstrated that the kinetic temperature of the ions is equal to the gas temperature and that it can be varied from 300 K down to 30 K.

Reduced Th22 cell proportion and prevention of atopic dermatitis in infants following maternal probiotic supplementation.

BACKGROUND: In the randomized, controlled study Probiotics in the Prevention of Allergy among Children in Trondheim (ProPACT), maternal probiotic supplementation reduced the incidence of atopic dermatitis (AD) in the offspring. In the current study, we hypothesized that the effect was mediated by a shift in the T helper (Th) cells in the children. OBJECTIVE: To examine whether Th cell proportions were affected by maternal probiotic supplementation and thus could mediate the preventive effect of probiotics on AD. METHODS: A total of 415 pregnant women were randomized to ingest a combination of Lactobacillus rhamnosus GG (LGG), Bifidobacterium animalis subsp. lactis Bb-12 (Bb-12) and Lactobacillus acidophilus La-5 (La-5) or placebo, and their offspring were assessed for AD during the first 2 years of life. Peripheral blood collected at 3 months of age was analysed for regulatory T cells (n=140) and Th subsets (n=77) including Th1, Th2, Th9, Th17 and Th22. RESULTS: The proportion of Th22 cells was reduced in children in the probiotic group compared to the placebo group (median 0.038% vs 0.064%, P=.009). The difference between the probiotic and placebo groups was also observed in the children who did not develop AD during the 2-year follow-up. The proportion of Th22 cells was increased in children who developed AD compared to the children who did not develop AD (0.090% vs 0.044%, P<.001). Mediation analysis indicated that the preventive effect of probiotics was partially mediated through the reduction in Th22 cells. CONCLUSION: Perinatal maternal probiotic supplementation with a combination of LGG, Bb-12 and La-5 reduced the proportion of Th22 cells in 3-month-old children. This may partially explain the preventive effect of probiotics on AD.

Transition from infant- to adult-like gut microbiota.

Transition from an infant to an adult associated gut microbiota with age through establishment of strict anaerobic bacteria remains one of the key unresolved questions in gut microbial ecology. Here a comprehensive comparative analysis of stool microbiota in a large cohort of mothers and their children sampled longitudinally up until 2 years of age using sequencing analysis tool was presented that allows realistic microbial diversity estimates. In this work, evidence for the switch from children to adult associated microbial profile between 1 and 2 years of age was provided, suggestively driven by Bifidobacterium breve. An Operational Taxonomic Unit (OTU) belonging to B. breve was highly prevalent in the population throughout the first year of life, and was negatively associated with detection of a range of adult-like OTUs. Although an adult profile was not fully established by 2 years of age, it was demonstrated that with regards to the most prevalent OTUs, their prevalence in the child population by then already resembled that of the adult population. Taken together, it was proposed that late-colonizing OTUs were recruited at a later stage and were not acquired at birth with the recruitment being controlled by gatekeeping OTUs until the age of 1 year.

Capturing metal-support interactions in situ during the reduction of a Re promoted Co/γ-Al2O3 catalyst.

The reduction of a Re promoted Co/γ-Al2O3 catalyst was monitored in situ by synchrotron X-ray powder diffraction (XRPD) under H2 environment. Whole powder pattern analysis revealed a non-linear expansion of the unit cell of γ-Al2O3 during the reduction process, suggesting the diffusion of Co cations into the structure of the support. The non-linear cell expansion coincided with the formation of a CoO phase. In addition, space resolved diffraction at the inlet and the outlet of the reactor evidenced a negative effect of the partial pressure of indigenous H2O(g) on the reduction process.

Leisure-time physical activity and disability pension: 9 years follow-up of the HUNT Study, Norway.

The objective of this study was to prospectively examine the association between leisure-time physical activity and risk of disability pension, as well as risk of disability pension because of musculoskeletal or mental disorders in a large population-based cohort. Data on participants aged 20-65 years in the Norwegian Nord-Trøndelag Health Study 1995-1997 (HUNT2) were linked to the National Insurance Database. Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals for disability pension across physical activity categories. During a follow-up of 9.3 years and 235,657 person-years, 1266 of 13,823 men (9%) and 1734 of 14,531 women (12%) received disability pension. Compared with individuals in the inactive group, those in the highly active group had a 50% lower risk of receiving disability pension (HR for men: 0.50, 0.40-0.64; women: 0.50, 0.39-0.63). After comprehensive adjustment for potential confounders, the risk remained 32-35% lower (HR for men: 0.68, 0.53-0.86; women: 0.65, 0.51-0.83). The associations were stronger for disability pension due to musculoskeletal disorders than mental disorders. In summary, we observed strong inverse associations between leisure-time physical activity and disability pension. Our findings strengthen the hypothesis that leisure-time physical activity may be important for occupational health in reducing disability pension.

Ternary recombination of H3(+) and D3(+) with electrons in He-H2 (D2) plasmas at temperatures from 50 to 300 k.

We present results of plasma afterglow experiments on ternary electron-ion recombination rate coefficients of H3(+) and D3(+) ions at temperatures from 50 to 300 K and compare them to possible three-body reaction mechanisms. Resonant electron capture into H3* Rydberg states is likely to be the first step in the ternary recombination, rather than third-body-assisted capture. Subsequent interactions of the Rydberg molecules with ambient neutral and charged particles provide the rate-limiting step that completes the recombination. A semiquantitative model is proposed that reconciles several previously discrepant experimental observations. A rigorous treatment of the problem will require additional theoretical work and experimental investigations.

Bifidobacterial succession and correlation networks in a large unselected cohort of mothers and their children.

Bifidobacteria are a major microbial component of infant gut microbiota, which is believed to promote health benefits for the host and stimulate maturation of the immune system. Despite their perceived importance, very little is known about the natural development of and possible correlations between bifidobacteria in human populations. To address this knowledge gap, we analyzed stool samples from a randomly selected healthy cohort of 87 infants and their mothers with >90% of vaginal delivery and nearly 100% breast-feeding at 4 months. Fecal material was sampled during pregnancy, at 3 and 10 days, at 4 months, and at 1 and 2 years after birth. Stool samples were predicted to be rich in the species Bifidobacterium adolescentis, B. bifidum, B. dentium, B. breve, and B. longum. Due to high variation, we did not identify a clear age-related structure at the individual level. Within the population as a whole, however, there were clear age-related successions. Negative correlations between the B. longum group and B. adolescentis were detected in adults and in 1- and 2-year-old children, whereas negative correlations between B. longum and B. breve were characteristic for newborns and 4-month-old infants. The highly structured age-related development of and correlation networks between bifidobacterial species during the first 2 years of life mirrors their different or competing nutritional requirements, which in turn may be associated with specific biological functions in the development of healthy gut.

Binary recombination of para- and ortho-H3+ with electrons at low temperatures.

Results of an experimental study of binary recombination of para- and ortho-H(3)(+) ions with electrons are presented. Near-infrared cavity-ring-down absorption spectroscopy was used to probe the lowest rotational states of H(3)(+) ions in the temperature range of 77-200 K in an H(3)(+)-dominated afterglow plasma. By changing the para/ortho abundance ratio, we were able to obtain the binary recombination rate coefficients for pure and para-H(3)(+) and ortho-H(3)(+). The results are in good agreement with previous theoretical predictions.

Modelling bacterial transmission in human allergen-specific IgE sensitization.

AIMS: The impact of bacterial transmission from mother to child on human allergy development is poorly understood. The aim of the present work was therefore to use a temporal collected dataset of 117 mothers and their children to model the potential effect of mother-to-child bacterial transmission on allergy (IgE) sensitization. METHODS AND RESULTS: We have recently shown a negative IgE correlation to high Escherichia coli levels until the age of 1 year, with a shift to positive correlation to high Bacteroides fragilis levels at the age of 2. In the present work, we used the previous published data to model the persistence and interaction effects of E. coli and B. fragilis with respect to IgE sensitization. Temporal modelling was made by first defining a stochastic model for sensitization state based on Markov chains and regression tree analyses. Subsequent simulations were used to determine the impact of mother-to-infant bacterial transmission. The regression tree analyses showed that E. coli colonization within 4 days was negatively correlated to sensitization, while lack of E. coli colonization at day 4 combined with B. fragilis colonization after 4 months was positively correlated. With Markov chain analyses, we found that E. coli was highly persistent in infants until the age of 4 months, while the persistence of B. fragilis increased with age. CONCLUSIONS: Simulations showed that the mother's bacterial composition correlated significantly to the child's IgE sensitization state at the age of 2 years. High E. coli and low B. fragilis levels in the mother were negatively correlated, while low E. coli and high B. fragilis were positively correlated to IgE. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results support that allergy could partly be communicable, being transferred from mother to infant through the gut microbiota.

Mother-to-child transmission of and multiple-strain colonization by Bacteroides fragilis in a cohort of mothers and their children.

Bacteroides fragilis represents an early infant colonizer with important host interactions. Our knowledge about the diversity, transmission, and persistence of this bacterium, however, is limited. Here, we addressed these questions using a combination of multilocus sequence typing (MLST) and variable-number tandem repeat (VNTR) sequence analyses. We used both culture-dependent and -independent typing. We genotyped B. fragilis in fecal samples from a cohort of 93 mothers and their children, with samples taken from the mothers and from the children at the ages 1 to 10 days, 4 months, 1 year, and 2 years. By MLST we found two main B. fragilis groups, which we denoted clades A and B. Direct typing of stool samples using the icd gene revealed seven sequence types, five within clade A and two within clade B. A single clade A sequence type, however, represented 79% of all the sequences. This sequence type was further subtyped using VNTR. VNTR subtyping revealed 16 different VNTR types. Based on the distribution patterns of these, we show mother-to-child transmission and multiple-strain colonization. We argue that negative host selection promotes the coexistence of multiple strains. The significance of our findings is that we have started unraveling the transmission and persistence patterns of one of the most important human gut colonizers.

Temporal variations in early gut microbial colonization are associated with allergen-specific immunoglobulin E but not atopic eczema at 2 years of age.

BACKGROUND: Intestinal microbiota undergoes substantial development during the first 2 years of life, important for intestinal immunologic development and maturation influencing systemic immune responses. OBJECTIVE: We aimed to investigate, using a prospective study design, whether allergen-specific IgE (sIgE) and atopic eczema are associated with variations in gut microbial colonization patterns in an unselected population during the first 2 years of life. METHODS: Faeces from 94 infants were repeatedly sampled from 10 days, 4 months, 1 and 2 years postnatal and analysed for 12 different bacterial species by quantitative real-time PCR. Venous blood samples from the infants were collected at 2 years of age and were analysed for sIgE for 12 specific allergens. The temporal gut colonization patterns for 42 sIgE-positive (sIgE≥0.35 kU/L) and 52 sIgE-negative children (sIgE<0.1 kU/L) were then compared. The association between colonization pattern and phenotype as atopic eczema according to UK Working Party (UKWP) criteria were also described. RESULTS: Subjects with atopic sensitization had lower levels of Escherichia coli at 4 months and 1 year, higher levels of Bifidobacterium longum at 1 year and lower levels of Bacteroides fragilis at 2 years. For E. coli and B. longum, the differences were only transient and had disappeared by 2 years of age. For other species, there were no differences in colonization patterns, and we found no association between colonization pattern and atopic eczema. CONCLUSIONS AND CLINICAL RELEVANCE: We found temporal and transient variations in gut microbial colonization patterns associated with differences in sIgE sensitization at 2 years of age. A full understanding of the principles and mechanisms that underlie intestinal microbial colonization and diversity and host-microbiota relationships will be pivotal for the development of therapeutic approaches that manipulate the intestinal microbiota to maintain human health. [ REGISTRATION NUMBER: ISRCTN28090297].

Probiotics in pregnant women to prevent allergic disease: a randomized, double-blind trial.

BACKGROUND: Previous reports have suggested that certain probiotics given to mothers and children at risk of atopy halves the incidence of atopic dermatitis (AD) at 2 years of age. OBJECTIVES: To examine if probiotics given to pregnant women in a nonselected population could prevent atopic sensitization or allergic diseases during the child's first 2 years. METHODS: In a randomized, double-blind trial of children from a nonselected maternal population (ClinicalTrials.gov identifier: NCT00159523), women received probiotic milk or placebo from 36 weeks of gestation to 3 months postnatally during breastfeeding. The probiotic milk contained Lactobacillus rhamnosus GG, L. acidophilus La-5 and Bifidobacterium animalis subsp. lactis Bb-12. Children with an itchy rash for more than 4 weeks were assessed for AD. At 2 years of age, all children were assessed for atopic sensitization, AD, asthma and allergic rhinoconjunctivitis. The intention-to-treat (ITT) analysis was enabled by multiple imputations. RESULTS: Four hundred and fifteen pregnant women were computer randomized. At 2 years, 138 and 140 children in the probiotic and the placebo groups, respectively, were assessed. In the ITT analysis, the odds ratio (OR) for the cumulative incidence of AD was 0·51 in the probiotic group compared with the placebo [95% confidence interval (CI) 0·30-0·87; P=0·013]. There were no significant effects on asthma (OR 0·68, 95% CI 0·26-1·80; P=0·437) or atopic sensitization (OR 1·52, 95% CI 0·74-3·14; P=0·254). CONCLUSIONS: Probiotics given to nonselected mothers reduced the cumulative incidence of AD, but had no effect on atopic sensitization.

Complementary and alternative medicine practitioner consultations among those who have or have had cancer in a Norwegian total population (Nord-Trøndelag Health Study): prevalence, socio-demographics and health perceptions.

The aim of the study was to identify the use of complementary and alternative medicine (CAM) practitioners among current and previous cancer patients in a total population. A secondary analysis of data from the Nord-Trøndelag Health Study (otherwise known as the HUNT 2 Study) - a total population survey conducted in central Norway - was undertaken. Analysis focused upon the response of 1406 individuals who reported to have or have had cancer and who answered a question on visits to CAM practitioners. The study identified 16.1% of respondents had visited a CAM practitioner in the prior 12 months compared with 12.8% in the total population, and the likelihood of consulting a CAM practitioner was significantly increased among those who had a university degree, who reported a lower perceived global health and who had experienced a health complaint during the last 12 months. Complementary and alternative medicine practitioner consultations among individuals with a previous or current malignant disease were highest for those with poor self-reported health status and with a recent health complaint. From the socio-demographic variables studied only the reporting of a university degree was significantly associated with higher CAM practitioner use.

Three-dimensional immunofluorescent double labelling using polyclonal antibodies derived from the same species: enterocytic colocalization of chylomicrons with Golgi apparatus.

Double immunolabelling is a useful technique to determine cellular colocalization of proteins, but is prone to false-positive staining because of cross-reactivity between antibodies. In this study, we established a simple and quick method to demonstrate the immunofluorescent double labelling with two rabbit-derived polyclonal antibodies. The principle used was to establish a dilution of primary antibody for the first protein of interest, which would only be detectable following biotin-avidin amplification. Thereafter, the second protein of interest was assessed via standard secondary antibody detection, ensuring no cross-reactivity with the first protein antibody-antigen complex. We successfully demonstrated the three-dimensional colocalization of enterocytic apolipoprotein B, an equivocal marker of intestinal lipoproteins with Golgi apparatus. Colocalization of apo B and Golgi apparatus (75.2 +/- 8.5%) is consistent with the purported mode of secretion of these macromolecules.

Severe symptoms of gastro-oesophageal reflux disease are associated with cardiovascular disease and other gastrointestinal symptoms, but not diabetes: a population-based study.

BACKGROUND: Few population-based studies have examined comorbidity in relation to gastro-oesophageal reflux disease (GERD). AIM: To study the association between cardiovascular disease, diabetes, gastrointestinal symptoms and GERD. METHODS: Population-based, cross-sectional, case-control study based on a large Norwegian health survey conducted in 1995-97. Among 65,333 participants, 3153 persons reporting severe reflux symptoms were defined as cases, and 40,210 persons without such symptoms were defined as controls. Data on cardiovascular disease, diabetes, gastrointestinal symptoms and potential confounders were collected through questionnaires. Odds ratios (OR) with 95% confidence intervals (CI) were estimated using unconditional logistic regression, in crude and adjusted models. RESULTS: In the crude models, positive associations were observed between myocardial infarction (OR 1.7, 95% CI 1.4-2.1), angina pectoris (OR 2.5, 95% CI 2.1-2.9) and stroke (OR 1.6, 95% CI 1.2-2.1) and risk of GERD. The associations were attenuated in the adjusted models, but remained significant for angina pectoris (OR 1.9, 95% CI 1.6-2.2). No association was observed between diabetes and GERD. Strong positive associations were seen between all studied gastrointestinal symptoms, i.e. nausea, diarrhoea and constipation, and risk of GERD. CONCLUSIONS: This population-based study indicates that myocardial infarction, angina pectoris, stroke and symptoms of nausea, diarrhoea and constipation are associated with GERD.

Severe gastro-oesophageal reflux symptoms in relation to anxiety, depression and coping in a population-based study.

BACKGROUND: The association between psychiatric disorders and gastro-oesophageal reflux symptoms is uncertain, and few population-based studies are available. AIM: To examine the association between psychiatric and psychological factors and reflux symptoms. METHODS: Population-based, cross-sectional, case-control study based on two health surveys conducted in the Norwegian county Nord-Trondelag in 1984-1986 and 1995-1997. Reflux symptoms were assessed in the second survey, including 65,333 participants (70% of the county's adult population). 3153 subjects reporting severe reflux symptoms were defined as cases and 40,210 subjects without symptoms were defined as controls. Data were collected in questionnaires. Odds ratio with 95% confidence intervals were estimated using unconditional logistic regression, in adjusted models. RESULTS: Subjects reporting anxiety without depression had a 3.2-fold (95% CI: 2.7-3.8) increased risk of reflux, subjects with depression without anxiety had a 1.7-fold (95% CI: 1.4-2.1) increased risk and subjects with both anxiety and depression had a 2.8-fold (95% CI: 2.4-3.2) increased risk, compared to subjects without anxiety/depression. We observed a weak inverse association between one measure of covert coping and risk of reflux and a weak positive association between another coping measure and risk of reflux. CONCLUSIONS: This population-based study indicates that anxiety and depression are strongly associated with reflux symptoms, while no consistent association regarding coping and reflux was found.

Atopic dermatitis in adolescent boys is associated with greater psychological morbidity compared with girls of the same age: the Young-HUNT study.

BACKGROUND: Having atopic dermatitis (AD) as well as other chronic diseases is often associated with reduced mental health. Adolescents with AD are thought to be especially vulnerable, but few studies have included an ample number of young people. OBJECTIVES: To study self-reported mental distress among boys and girls 13-19 years of age with AD compared with mental distress among healthy adolescents as well as mental distress among adolescents with other chronic diseases or complaints, such as headache, neck or shoulder pain, asthma, allergy and rhinitis. METHODS: The Young-HUNT study was conducted as a cross-sectional, population-based survey in 1995-97. All students in Nord-Trondelag County, Norway, aged 13-19 years were invited, and some 89% participated. A questionnaire on mental and somatic health, life-style and social conditions was completed during one school hour. RESULTS: A total of 4384 girls and 4433 boys participated. The prevalence of mental distress was higher among older teenagers, and more than every fourth girl aged 17-19 reported mental distress. Although more girls than boys reported mental distress, AD, headache and neck or shoulder pain, the odds for reporting both AD and mental distress were higher for boys [odds ratio (OR) = 2.1 (1.6-2.9)] compared with girls [OR = 1.3 (1.1-1.6)]. A corresponding sex difference in reporting mental distress was also seen for some other chronic diseases or complaints. CONCLUSIONS: In adolescents aged 13-19 years there was a strong and significant association between self-reported mental distress and AD as well as headache and neck or shoulder pain for both sexes. Although boys reported fewer complaints as AD, they perceived the complaints a heavier burden than did the girls.

Reducing sick leave by minimal postal intervention: a randomised, controlled intervention study.

BACKGROUND: The lack of efficient medical interventions for combating increasing sickness absence rates has lead to the introduction of alternative measures initiated by the Norwegian National Insurance Service or at workplaces. AIM: To determine whether minimal postal intervention had any effect on the length of sick leave. METHODS: Randomised, controlled trial with a one year follow up in Northern Norway in 1997 and 1998; 990 consecutive newly sick-listed persons with musculoskeletal or mental disorders were studied. Within the intervention group, 495 eligible sick-listed persons received a general information letter and a questionnaire as their sick leave passed 14 days. Possible intervention effects were analysed by survival analysis of the probability of returning to work within one year, and logistic regressions with benefits at one year as the dependent variable. RESULTS: The overall reduction of 8.3 (95% CI -22.5 to 6.0) calendar days in mean length of sick leaves in the intervention group compared to controls, was not statistically significant. However, intervention significantly reduced length of sick leaves in subgroups with mental disorders, and with rheumatic disorders and arthritis, and overall for sick leaves lasting 12 weeks or more. Young people with low back pain showed an adverse effect to intervention. The overall relative risk of receiving benefits due to sickness after one year in the intervention group was 0.69 (95% CI 0.51 to 0.93) compared to controls. CONCLUSION: The results should encourage employers, insurance institutions, and authorities to initiate challenges as questions on the length of sick leave and possible modified work measures, during the first few weeks of sick leave, for at least some groups of sick-listed persons.

Have the implementation of a new specialised emergency medical service influenced the pattern of general practitioners involvement in pre-hospital medical emergencies? A study of geographic variations in alerting, dispatch, and response.

OBJECTIVES: Emergency medical service systems in Norway are based on equity and equality. A toll free number (113) and criteria based dispatch are crucial components. The establishment of an emergency medical system (EMS) manned by an air and ground emergency physician (EP) has challenged the role of the general practitioner (GP) in emergency medical care. We investigated whether there were any geographical differences in the use of 113, alerts to GPs by the emergency medical dispatch centres (EMDCs), and of the presence of GPs on scene in medical emergencies leading to a turnout of the EP manned EMS. METHODS: This was a prospective, observational cohort study of 385,000 inhabitants covered by the two EMDCs of Rogaland county, Norway, including 1035 on scene missions of the EP manned EMS during the period 1998-99. RESULTS: The proportion of emergency calls routed through 113 was significantly lower, the proportion of alerts to GPs significantly higher, and the proportions of GPs on scene significantly higher in rural than urban areas. CONCLUSION: We found geographical differences in the involvement of GPs in pre-hospital emergency medical situations, probably caused by a specialised emergency medical service system including an EMDC and an air and ground EP manned EMS. There were geographical differences in public use of the toll free 113, and alerts to GPs by the EMDCs, which is likely to result from geographical conditions and proximity to medical resources. Future organisation of the EMS has to reflect this to prevent unplanned and unwanted autonomously emerging EMS systems.