The C(3P) + NH3 reaction in interstellar chemistry: II. Low temperature rate constants and modeling of NH, NH2 and NH3 abundances in dense interstellar clouds

A continuous supersonic flow reactor has been used to measure rate constants for the C + NH3 reaction over the temperature range 50 to 296 K. C atoms were created by the pulsed laser photolysis of CBr4. The kinetics of the title reaction were followed directly by vacuum ultra-violet laser induced fluorescence (VUV LIF) of C loss and through H formation. The experiments show unambiguously that the reaction is rapid at 296 K, becoming faster at lower temperatures, reaching a value of 1.8 10-10 cm3 molecule-1 s-1 at 50 K. As this reaction is not currently included in astrochemical networks, its influence on interstellar nitrogen hydride abundances is tested through a dense cloud model including gas-grain interactions. In particular, the effect of the ortho-to-para ratio of H2 which plays a crucial role in interstellar NH3 synthesis is examined

Flow tube studies of the C(3P) reactions with ethylene and propylene

International audienceProduct detection studies of C(3P) atom reactions with ethylene, C2H4(X1Ag) and propylene, C3H6(X1A′) are carried out in a flow tube reactor at 332 K and 4 Torr (553.3 Pa) under multiple collision conditions. Ground state carbon atoms are generated by 193 nm laser photolysis of carbon suboxide, C3O2 in a buffer of helium. Thermalized reaction products are detected using tunable VUV photoionization and time of flight mass spectrometry. For C(3P) + ethylene, propargyl (C3H3) is detected as the only molecular product in agreement with previous studies on this reaction. The temporal profiles of the detected ions are used to discriminate C(3P) reaction products from side reaction products. For C(3P) + propylene, two reaction channels are identified through the detection of methyl (CH3) and propargyl (C3H3) radicals for the first channel and C4H5 for the second one. Franck–Condon Factor simulations are employed to infer the C4H5-isomer distribution. The measured 1:4 ratio for the i-C4H5 isomer relative to the methylpropargyl isomers is similar to the C4H5 isomer distribution observed in low-pressure flames and differs from crossed molecular beams data. The accuracy of these isomer distributions is discussed in view of large uncertainties on the photoionization spectra of the pure C4H5 isomer

Maternal prenatal depression is associated with decreased placental expression of the imprinted gene PEG3.

BACKGROUND: Maternal prenatal stress during pregnancy is associated with fetal growth restriction and adverse neurodevelopmental outcomes, which may be mediated by impaired placental function. Imprinted genes control fetal growth, placental development, adult behaviour (including maternal behaviour) and placental lactogen production. This study examined whether maternal prenatal depression was associated with aberrant placental expression of the imprinted genes paternally expressed gene 3 (PEG3), paternally expressed gene 10 (PEG10), pleckstrin homology-like domain family a member 2 (PHLDA2) and cyclin-dependent kinase inhibitor 1C (CDKN1C), and resulting impaired placental human placental lactogen (hPL) expression. METHOD: A diagnosis of depression during pregnancy was recorded from Manchester cohort participants' medical notes (n = 75). Queen Charlotte's (n = 40) and My Baby and Me study (MBAM) (n = 81) cohort participants completed the Edinburgh Postnatal Depression Scale self-rating psychometric questionnaire. Villous trophoblast tissue samples were analysed for gene expression. RESULTS: In a pilot study, diagnosed depression during pregnancy was associated with a significant reduction in placental PEG3 expression (41%, p = 0.02). In two further independent cohorts, the Queen Charlotte's and MBAM cohorts, placental PEG3 expression was also inversely associated with maternal depression scores, an association that was significant in male but not female placentas. Finally, hPL expression was significantly decreased in women with clinically diagnosed depression (44%, p < 0.05) and in those with high depression scores (31% and 21%, respectively). CONCLUSIONS: This study provides the first evidence that maternal prenatal depression is associated with changes in the placental expression of PEG3, co-incident with decreased expression of hPL. This aberrant placental gene expression could provide a possible mechanistic explanation for the co-occurrence of maternal depression, fetal growth restriction, impaired maternal behaviour and poorer offspring outcomes.The Manchester cohort was supported by Manchester National Institute for Health Research (NIHR) Biomedical Research. The Queen Charlotte’s cohort was supported by the Medical Research Council (MRC) (Eurostress), National Institutes of Health (R01MH073842) and the Genesis Research Trust. The MBAM cohort was supported by the Genesis Research Trust. A.B.J. was supported by a Biotechnology and Biological Sciences Research Council (BBSRC) Doctoral Training Grants (DTG) studentship and subsequently MRC project grant MR/M013960/1. S.J.T. was supported by BBSRC project grant BB/J015156/1. L.E.C. was supported by an Imperial College London Ph.D. studentship and both L.E.C. and P.G.R were supported by the NIHR Imperial Biomedical Research Centre

Regulatory and Activated T Cells in Human Schistosoma haematobium Infections

Acquired immunity against helminths is characterised by a complex interplay between the effector Th1 and Th2 immune responses and it slowly manifests with age as a result of cumulative exposure to parasite antigens. Data from experimental models suggest that immunity is also influenced by regulatory T cells (Treg), but as yet studies on Treg in human schistosome infections are limited

Incorporating a Rapid-Impact Package for Neglected Tropical Diseases with Programs for HIV/AIDS, Tuberculosis, and Malaria: A comprehensive pro-poor health policy and strategy for the developing world

Hotez et al. argue that achieving success in the global fight against HIV/AIDS, tuberculosis, and malaria may well require a concurrent attack on the neglected tropical diseases

Maternal influences on fetal brain development: the role of nutrition, infection and stress, and the potential for intergenerational consequences.

An optimal early life environment is crucial for ensuring ideal neurodevelopmental outcomes. Brain development consists of a finely tuned series of spatially and temporally constrained events, which may be affected by exposure to a sub-optimal intra-uterine environment. Evidence suggests brain development may be particularly vulnerable to factors such as maternal nutrition, infection and stress during pregnancy. In this review, we discuss how maternal factors such as these can affect brain development and outcome in offspring, and we also identify evidence which suggests that the outcome can, in many cases, be stratified by socio-economic status (SES), with individuals in lower brackets typically having a worse outcome. We consider the relevant epidemiological evidence and draw parallels to mechanisms suggested by preclinical work where appropriate. We also discuss possible transgenerational effects of these maternal factors and the potential mechanisms involved. We conclude that modifiable factors such as maternal nutrition, infection and stress are important contributors to atypical brain development and that SES also likely has a key role

Fetal programming of neuropsychiatric disorders by maternal pregnancy depression: a systematic mini review

BACKGROUND: Maternal depression complicates a large proportion of pregnancies. Current evidence shows numerous harmful effects on the offspring. Reviews, which include depression, concluded that stress has harmful effects on the offspring's outcomes neuro-cognitive development, temperament traits, and mental disorders. OBJECTIVE: This mini review of recent studies, sought to narrow the scope of exposure and identify studies specifically assessing prenatal depression and offspring neuropsychiatric outcomes. STUDY ELIGIBILITY CRITERIA: The review included longitudinal, cohort, cross-sectional, clinical, quasi-experimental, epidemiological, or intervention study designs published in English from 2014 to 2018. PARTICIPANTS: Study populations included mother-child dyads, mother-father-child triads, mother-alternative caregiver-child triads, and family studies utilizing sibling comparisons. METHODS: We searched PubMED and Web of Science. Study inclusion and data extraction were based on standardized templates. The quality of evidence was assessed using the Newcastle-Ottawa Scale (NOS). RESULTS: Thirteen studies examining neuropsychiatric outcomes were included. We judged the evidence to be moderate to high quality. CONCLUSIONS: Our review supports that maternal prenatal depression is associated with neuropsychiatric adversities in children.Peer reviewe