Impact of maternal smoking on the development of gut microbiome in infants

Abstract. It has recently been suggested that the development of human microbiome may start in the prenatal period. This hypothesis is based on several studies reporting diverse microbiome in the first-pass meconium, the first stool after birth, formed before birth in utero. Earlier, maternal factors, such as maternal overweight, antibiotics and biodiversity of the livening environment during pregnancy have been reported to associate with the microbiome in the first pass meconium. Maternal smoking is a known risk factor for the subsequent health of children. Gut microbiome composition has earlier been associated with several diseases in childhood. In this study, we set out to investigate whether maternal smoking during pregnancy has an impact on the gut microbiome composition in the first pass meconium, developed in the fetal period. To test this hypothesis, we first made a literature review. PubMed search in November 2019, with the keywords maternal smoking [title] AND microbio* [title], found a single study of the subject. Based on the literature review, in adults, an association between smoking and the changes in gut microbiome have been reported, such as a decrease of abundance of Firmicutes phylum and increase in Bacteroidetes phylum in gut microbiome. We then investigated 131 first-pass meconium samples with earlier bacterial 16S gene next generation sequencing-based microbiome analysis and maternal smoking status available. In our study, a cohort of newborn infants, altogether 5 (3.8%) of 131 mothers reported smoking during pregnancy. The relative abundances of Bacteroidetes and Proteobacteria phyla were higher and the relative abundance of Firmicutes phylum was lower in those infants exposed to maternal smoking during pregnancy. In addition, the infants exposed to maternal smoking had less diverse gut microbiome and the number of the operational taxonomic units (OTUs) was lower. Based on the literature review and our preliminary study with meconium samples, we suggest that the association of maternal smoking and microbiome in the first stool should be further evaluated in a larger cohort since maternal smoking may have clinically significant impact on early gut microbiome of newborn infants

Electrode thickness measurement of a Si(Li) detector for the SIXA array

Cathode electrodes of the Si(Li) detector elements of the SIXA X-ray spectrometer array are formed by gold-palladium alloy contact layers. The equivalent thickness of gold in one element was measured by observing the characteristic L-shell X-rays of gold excited by monochromatised synchrotron radiation with photon energies above the L3 absorption edge of gold. The results obtained at 4 different photon energies below the L2 edge yield an average value of 22.4(35) nm which is consistent with the earlier result extracted from detection efficiency measurements. PACS: 29.40.Wk; 85.30.De; 07.85.Nc; 95.55.Ka Keywords: Si(Li) detectors, X-ray spectrometers, X-ray fluorescence, detector calibration, gold electrodes, synchrotron radiationComment: 10 pages, 4 PostScript figures, uses elsart.sty, submitted to Nucl. Instrum. Meth.

Improving the spatial and statistical accuracy in X-ray Raman scattering based direct tomography

An algorithm to simultaneously increase the spatial and statistical accuracy of X-ray Raman scattering (XRS) based tomographic images is presented. Tomography that utilizes XRS spectroscopy signals as a contrast for the images is a new and promising tool for investigating local atomic structure and chemistry in heterogeneous samples. The algorithm enables the spatial resolution to be increased based on a deconvolution of the optical response function of the spectrometer and, most importantly, it allows for the combination of data collected from multiple analyzers and thus enhances the statistical accuracy of the measured images.Peer reviewe

Anisotropic excitonic effects in the energy loss function of hexagonal boron nitride

We demonstrate that the valence energy-loss function of hexagonal boron nitride (hBN) displays a strong anisotropy in shape, excitation energy and dispersion for momentum transfer q parallel or perpendicular to the hBN layers. This is manifested by e.g. an energy shift of 0.7 eV that cannot be captured by single-particle approaches and is a demonstration of a strong anisotropy in the two-body electron-hole interaction. Furthermore, for in-plane directions of q we observe a splitting of the -plasmon in the M direction that is absent in the K direction and this can be traced back to band-structure effects.Comment: 10 pages, 4 figure

K -shell diagram and hypersatellite spectra of 4d transition elements

The K-shell diagram (K alpha(1,2) and K beta(1,3)) and hypersatellite (HS) (K-h alpha(1,2)) spectra of Y, Zr, Mo, and Pd have been measured with high energy-resolution using photoexcitation by 90 keV synchrotron radiation. Comparison of the measured and ab initio calculated HS spectra demonstrates the importance of quantum electrodynamical (QED) effects for the HS spectra. Phenomenological fits of the measured spectra by Voigt functions yield accurate values for the shift of the HS from the diagram lines, the splitting of the HS lines, and their intensity ratio. Good agreement with theory was found for all quantities except for the intensity ratio, which is dominated by the intermediacy of the coupling of the angular momenta. The observed deviations imply that our current understanding of the variation of the coupling scheme from LS to jj across the periodic table may require some revision.The K-shell diagram (K alpha(1,2) and K beta(1,3)) and hypersatellite (HS) (K-h alpha(1,2)) spectra of Y, Zr, Mo, and Pd have been measured with high energy-resolution using photoexcitation by 90 keV synchrotron radiation. Comparison of the measured and ab initio calculated HS spectra demonstrates the importance of quantum electrodynamical (QED) effects for the HS spectra. Phenomenological fits of the measured spectra by Voigt functions yield accurate values for the shift of the HS from the diagram lines, the splitting of the HS lines, and their intensity ratio. Good agreement with theory was found for all quantities except for the intensity ratio, which is dominated by the intermediacy of the coupling of the angular momenta. The observed deviations imply that our current understanding of the variation of the coupling scheme from LS to jj across the periodic table may require some revision.The K-shell diagram (K alpha(1,2) and K beta(1,3)) and hypersatellite (HS) (K-h alpha(1,2)) spectra of Y, Zr, Mo, and Pd have been measured with high energy-resolution using photoexcitation by 90 keV synchrotron radiation. Comparison of the measured and ab initio calculated HS spectra demonstrates the importance of quantum electrodynamical (QED) effects for the HS spectra. Phenomenological fits of the measured spectra by Voigt functions yield accurate values for the shift of the HS from the diagram lines, the splitting of the HS lines, and their intensity ratio. Good agreement with theory was found for all quantities except for the intensity ratio, which is dominated by the intermediacy of the coupling of the angular momenta. The observed deviations imply that our current understanding of the variation of the coupling scheme from LS to jj across the periodic table may require some revision.Peer reviewe

Direct observation of the momentum distribution and renormalization factor in lithium

We have measured the momentum distribution and renormalization factor Z(kF) in liquid and solid lithium by high-resolution Compton scattering. High-resolution data over a wide momentum range exhibit a clear feature of the renormalization and a sharp drop of momentum densities at the Fermi momentum k(F). These results are compared with those computed by quantum Monte Carlo simulation performed both on a disordered crystal and a liquid exhibiting very good agreement. Asymptotic behavior of the experimental and theoretical momentum distributions are examined to estimate Z(kF). The experimentally obtained Z(kF) = 0.43(-0.01)(+0.11) for liquid Li and 0.54(-0.02)(+0.11) for solid Li are in good agreement with theoretical results of 0.54 +/- 0.01 and 0.64 +/- 0.01, respectively.Peer reviewe

Comparing C-60 and C-70 as acceptor in organic solar cells : Influence of the electronic structure and aggregation size on the photovoltaic characteristics

The difference in aggregation size of the C-60 and C-70 fullerenes affect the photovoltaic performance of devices assembled in the so-called bilayer architecture with poly [2,7-(9,9- dioctyl- dibenzosilole)- alt-4,7- bis(thiophen-2-yl)benzo- 2,1,3- thiadiazole] (PSiF-DBT) as the electron donor material. Despite the better performance of the C-70 devices, which is related to the high absorption coefficient in the visible range and the superior charge transport properties, the short-circuit current variation upon annealing treatment at 100 degrees C is approximately twice bigger when the C-60 is the acceptor. We attribute this effect to the tendency of C-60 in form smaller aggregate domains relatively to the C-70. The increased roughness on the polymeric surface after annealing results in an enhanced donor/acceptor contact area and assists the fullerene diffusion deeper inside the polymeric layer. This effect leads to a better mixing between donor and acceptor species and create a interpenetrating layer close to the so-called bulk heterojunction. Since C-60 forms smaller aggregates, this mechanism is more pronounced for this molecule. Therefore, a significant variation in the performance of the C-60 devices is observed after this kind of treatment. Density Functional Theory calculations of the potential energy of interaction between two fullerene molecules and X-Ray measurements gives evidences to support this idea. In addition, combining spectrally resolved external quantum efficiency measurements with optical modeling our results also indicate the occurrence of the bilayer interfacial mixing for PSiF-DBT/C-60.Peer reviewe

Incidence and risk factors for dental pathology in patients planned for elective total hip or knee arthroplasty

Background and Aims: To prevent severe prosthetic joint infections, a dental examination is usually recommended prior to arthroplasty, even sometimes regarded resource- and time-consuming. The aim of this study was to determine whether a risk factor-based algorithm could be created to send only selected patients for dental clearance. Materials and Methods: A prospective study of 952 patients scheduled for elective arthroplasty was performed. Patients filled out a questionnaire regarding potential risk factors for dental infections, and dentists documented patients' oral health and interventions performed (data available for 731 patients). Results: Of the patients, 215 (29.4%) failed dental clearance; a total of 432 teeth were extracted, 32 patients (4.4%) required root canal treatment, and 37 patients (5.1%) had severe periodontitis. Independent risk factors for failure were history of root canal treatment (odds ratio: 2.282, 95% confidence interval: 1.346-3.869, p = 0.020), use of tobacco products (odds ratio: 1.704, 95% confidence interval: 1.033-2.810, p = 0.037), dental visit indicated by oral symptoms within 3 months (odds ratio: 1.828, 95% confidence interval: 1.183-2.827, p = 0.007), or visit to a dentist within 6 months (odds ratio: 1.538, 95% confidence interval: 1.063-2.224, p = 0.022). Regular dental examination was a preventive factor (odds ratio: 0.519, 95% confidence interval: 0.349-0.773, p = 0.001). However, based on the examined risk factors, no sufficiently large group of patients at lesser risk for dental infections could be identified. Conclusion: Because of the high need for dental care revealed by our unselected patient population, the inspection and treatment of dental pathology of all patients are important interventions prior to elective arthroplasty.Peer reviewe

A Novel 2D Folding Technique for Enhancing Fermi Surface Signatures in the Momentum Density: Application to Compton Scattering Data from an Al-3at%Li Disordered Alloy

We present a novel technique for enhancing Fermi surface (FS) signatures in the 2D distribution obtained after the 3D momentum density in a crystal is projected along a specific direction in momentum space. These results are useful for investigating fermiology via high resolution Compton scattering and positron annihilation spectroscopies. We focus on the particular case of the (110) projection in an fcc crystal where the standard approach based on the use of the Lock-Crisp-West (LCW) folding theorem fails to give a clear FS image due to the strong overlap with FS images obtained through projection from higher Brillouin zones. We show how these superposed FS images can be disentangled by using a selected set of reciprocal lattice vectors in the folding process. The applicability of our partial folding scheme is illustrated by considering Compton spectra from an Al-3at%Li disordered alloy single crystal. For this purpose, high resolution Compton profiles along nine directions in the (110) plane were measured. Corresponding highly accurate theoretical profiles in Al-3at%Li were computed within the local density approximation (LDA)-based Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) first-principles framework. A good level of overall accord between theory and experiment is obtained, some expected discrepancies reflecting electron correlation effects notwithstanding, and the partial folding scheme is shown to yield a clear FS image in the (110) plane in Al-3%Li.Comment: 24 pages, 8 figures, to appear in Phys. Rev.