285 results on '"Taglauer, E"'
Search Results
252. Surface Structure Investigation with Ion Scattering and Scanning Tunneling Microscopy at Oxygen and Nitrogen Covered CU3Au Surfaces
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Niehus, Horst, Voetz, Matthias, Achete, Carlos, Morgenstern, Karina, Comsa, George, MacDonald, R. J., editor, Taglauer, E. C., editor, and Wandelt, K. R., editor
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- 1996
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253. Surface States on Metals
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Goldmann, A., Matzdorf, R., MacDonald, R. J., editor, Taglauer, E. C., editor, and Wandelt, K. R., editor
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- 1996
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254. Surface Structural Determination by VLEED Analysis
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Thurgate, S. M., Sun, Chang, Hitchen, G., MacDonald, R. J., editor, Taglauer, E. C., editor, and Wandelt, K. R., editor
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- 1996
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255. 3-D Surface Structure Analysis by X-Ray Diffraction
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Moritz, W., Meyerheim, H. L., MacDonald, R. J., editor, Taglauer, E. C., editor, and Wandelt, K. R., editor
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- 1996
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256. Tensor-LEED, Diffuse LEED, and LEED Holography
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Heinz, K., MacDonald, R. J., editor, Taglauer, E. C., editor, and Wandelt, K. R., editor
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- 1996
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257. Spectromicroscopy of catalytic relevant processes with sub-micron resolution.
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Gu¨nther, S., Esch, F., Gregoratti, L., Marsi, M., Kiskinova, M., Schubert, U. A., Grotz, P., Kno¨zinger, H., Taglauer, E., Schu¨tz, E., Schaak, A., and Imbihl, R.
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SPECTRUM analysis , *MICROSCOPY , *ELECTRON microscopy - Abstract
The capabilities of the Scanning Photo Electron Microscope (SPEM) at ELETTRA as a unique probing tool in the field of catalysis and surface science are illustrated presenting results of two recent investigations. The lateral resolution and the high surface sensitivity of the SPEM has enabled imaging the initial steps of the spreading processes of MoO[sub 3] crystals on an alumina support surface, a model system of a catalyst used in petrochemistry. In the second study the local adsorbate coverage inside a pulse of a chemical wave occurring in the catalytic NO + H[sub 2] reaction on a Rh(110) single crystal surface has been determined. The microscope was used to monitor the sample surface in situ during the reaction and thus characterizing a temporal and spatial inhomogeneous system. The so-called excitation cycle of the pulse formation has been verified and the adsorbate gradient inside a chemical wave was measured. [ABSTRACT FROM AUTHOR]
- Published
- 2000
258. Time-resolved measurements of hydrogen and deuterium fluxes in the ASDEX plasma boundary
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Taglauer, E.
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- 1982
259. LEIS: A reliable tool for surface composition analysis?
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Primetzhofer, D., Markin, S.N., Juaristi, J.I., Taglauer, E., and Bauer, P.
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HELIUM ions , *METALLIC surfaces , *POLYCRYSTALS , *TIME-of-flight mass spectrometry , *COLLISIONS (Nuclear physics) , *COPPER , *SILVER ,SCATTERING - Abstract
Abstract: Different single and polycrystalline surfaces of Cu and Ag have been investigated by time-of-flight low-energy ion scattering using 4He+ ions. The fraction of ions that survived single scattering from the outermost surface layers, P+, was measured in different neutralization regimes. At low energies, a distinct difference in P+ was observed for non-equivalent Cu crystal surfaces for projectiles backscattered in a single collision. The polycrystalline surface was found to exhibit similar neutralization behaviour as the (111) single crystal surface. At higher energies, P+ shows a strong dependence on the angular orientation of the single crystal. The impact of these findings on quantitative surface composition analysis by LEIS is discussed. [Copyright &y& Elsevier]
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- 2009
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260. Strength of the interatomic potential derived from angular scans in LEIS
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Primetzhofer, D., Markin, S.N., Draxler, M., Beikler, R., Taglauer, E., and Bauer, P.
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ATOM-atom collisions , *METALLIC whiskers , *COPPER crystals , *MOLECULAR dynamics , *ION scattering , *MONTE Carlo method - Abstract
Abstract: Angular scans were performed for a Cu(100) single crystal and He+ ions. The results were compared to MARLOWE, KALYPSO and FAN simulations to obtain information on the interaction potential. The influence of the used evaluation procedure on the deduced scattering potential was investigated. The scattering potential is found to be weaker than what is predicted by an uncorrected TFM potential. It was found that the use of a single screening correction factor is applicable in a wide range of impact parameters. It is further shown that selection of single scattering trajectories and a limitation of information depth to the surface layers is possible for neutral and charge integrated spectra. [Copyright &y& Elsevier]
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- 2008
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261. On the surface sensitivity of angular scans in LEIS
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Primetzhofer, D., Markin, S.N., Kolarova, R., Draxler, M., Beikler, R., Taglauer, E., and Bauer, P.
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IONS , *SPECTRUM analysis , *NEUTRAL beams , *SPHERICAL astronomy - Abstract
Abstract: A Cu(100) surface has been investigated by means of time-of-flight low-energy ion scattering using 4He+ ions. Polar and azimuth scans have been performed. The evaluation of the obtained spectra demonstrates the influence of background contributions to the overall yield. Selection of single scattering processes was achieved by background subtraction. This allows for high surface sensitivity even for neutral scattering spectra. [Copyright &y& Elsevier]
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- 2007
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262. Ion and neutral scattering spectra in LEIS
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Draxler, M., Zeppenfeld, P., Beikler, R., Taglauer, E., and Bauer, P.
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SCATTERING (Physics) , *SPECTRUM analysis , *PROPERTIES of matter , *COMPUTER simulation - Abstract
Abstract: Low energy ions scattering (LEIS) set-ups equipped with a time-of-flight (TOF) detection system can achieve an experimental resolution <1% for He ions at an energy of about 1keV, corresponding to sub-monolayer depth resolution. Furthermore, spectra of scattered neutrals reveal interesting information on the electronic interaction of the projectiles with the sample. We compare experimental TOF-LEIS spectra to Monte-Carlo simulations (MARLOWE) and discuss what one can learn from this comparison about elastic scattering (single scattering versus multiple scattering), about inelastic scattering (local versus non-local electronic energy loss) and about typical trajectories (validity of single scattering model, information depth). Our present understanding of ion and neutral scattering spectra in LEIS is discussed along these lines and results are presented for scattering of He+ ions from polycrystalline Au. [Copyright &y& Elsevier]
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- 2005
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263. Deuterium adsorption on W(100) studied by LEIS and DRS
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Bastasz, R., Medlin, J.W., Whaley, J.A., Beikler, R., and Taglauer, E.
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SURFACE chemistry , *ION scattering , *NUCLEAR reactions , *ADSORPTION (Chemistry) - Abstract
The location of deuterium adsorbed on W(100) has been studied using a combination of angle-resolved low-energy ion scattering (LEIS) and direct recoil spectroscopy (DRS). These techniques provide real-space data on both substrate and adsorbate surface structure. Adsorption of D on W(100) at 300 K has a strong effect on the azimuthal distribution of Ne+ scattering signal intensity from W, completely suppressing the sharp peaks seen on the clean surface every 90°, which result from Ne+ collisions with exposed second-layer W atoms. Concurrently with D adsorption, D+ recoil emission from the surface is observed with an angular distribution showing broad peaks aligned along the 〈100〉 directions. MARLOWE simulations of Ne+ scattering from the clean W(100) surface and of Ne+ scattering and D+ recoil emission from the saturated W(100) surface are all in good agreement with the LEIS and DRS data when adsorbed D atoms are located in fourfold hollow sites. [Copyright &y& Elsevier]
- Published
- 2004
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264. A low-energy ion scattering study of Al(1 1 0) surface melting
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Pedemonte, L., Bracco, G., Beikler, R., Taglauer, E., Robin, A., and Heiland, W.
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ALUMINUM , *SPECTRUM analysis - Abstract
The thermal behaviour of the (1 1 0) surface of aluminum is investigated by low-energy ion scattering along the
〈1 1¯ 0〉 and〈0 0 1〉 azimuthal directions in the temperature range between 300 and 910 K. Surface channeling mode and neutral impact collision ion scattering spectroscopy are used. Surface melting is observed and information on the evolution of the surface structure is gained with the help of simulations performed with the MARLOWE code. Experimental evidence for residual short range order is obtained along both azimuths within the quasi-liquid layer which probably consists of groups of surface atoms in correlated motion. [Copyright &y& Elsevier]- Published
- 2003
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265. Steps, facets and nanostructures: investigations of Cu (11n) surfaces.
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Reinecke, N., Reiter, S., Vetter, S., and Taglauer, E.
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COPPER surfaces , *NANOSTRUCTURES , *MATERIALS science - Abstract
Step structure and dynamics and adsorbate-induced reconstruction of stepped surfaces are useful features for investigating fundamental surface phenomena and their practical consequences. In this respect, vicinal Cu (11n) surfaces with n=3, 5 and 9 were studied by scanning tunneling microscopy (STM) at 300 K. While the regular monoatomic steps fluctuate for Cu (119), they are apparently stabilized for n≤5 by their strong repulsive interaction and this leads to a very low kink activity. In addition to the regular steps, the formation of double steps was observed as a particular phenomenon on those surfaces. These double steps determine the dynamic behavior at room temperature. By applying existing models for the fluctuations of the step positions in space and time, the formation energy for kinks at these double steps was determined to be 0.16 eV for Cu (115). According to this evaluation, diffusion along step edges is the dominating mass-transport mechanism. A model for the structure of the double steps and for the atomic displacement processes necessary for kink migration at these steps is presented. Complete faceting is observed for these surfaces upon oxygen adsorption at elevated temperatures (around 500 K) and was studied in detail for n=5 and 9. Both surfaces reconstruct into two types of {104} facets and a third facet, the orientation of which is determined by the macroscopic crystal orientation. The facet size is governed by the formation kinetics and can be controlled by varying the crystal temperature or the oxygen partial pressure. The formation kinetics is discussed as a nucleation and growth process and the relevant parameters are given. Facets within a range of size between 5 nm and 100 nm could thus be produced. They remained stable at ambient atmosphere, up to about 620 K, and also if covered by additional metal layers such as Ni. [ABSTRACT FROM AUTHOR]
- Published
- 2002
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266. Li + and He + ion scattering from clean and oxygen covered Ni(110) surfaces
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Englert, W., Taglauer, E., and Heiland, W.
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- 1982
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267. Neutralization of low energy He+ ions by Cu in the Auger regime
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Markin, S.N., Primetzhofer, D., Valdés, J.E., Taglauer, E., and Bauer, P.
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NEUTRALIZATION (Chemistry) , *POLYCRYSTALS , *IONS , *ELECTRONS - Abstract
Abstract: Neutralization of light 4He+ ions in backscattering geometry is studied on a single crystalline Cu(100) and on a poly crystalline Cu-poly surfaces by means of direct comparison of the ion yields. Below 2keV neutralization is only restricted to the Auger transition involving two electrons. Measurements in this regime revealed a ∼35% higher ion fraction for the single crystal Cu(100) with respect to the Cu-poly. The observed difference in the neutralization probability is ascribed to a different extension of the electron jellium edge, resulting from different atomic arrangement. [Copyright &y& Elsevier]
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- 2007
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268. Study of the sorption of CO on W and Ni single-crystal surfaces by ion scattering
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Taglauer, E
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- 1978
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269. Sputtering of chemisorbed nitrogen from single-crystal planes of tungsten and molybdenum
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Taglauer, E
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- 1987
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270. Partial pressure analysis using a two-chamber gauge together with an ion-- electron converter.
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Taglauer, E
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- 1973
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271. SMALL-ANGLE SCATTERING OF SUBTHERMAL NEUTRONS FROM DEFORMED POLYCRYSTALLINE COPPER.
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Taglauer, E
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- 1968
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272. Bombardment induced surface damage in a nickel single crystal observed by ion scattering and LEED
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Taglauer, E
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- 1973
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273. Characteristics of an ion source for surface research in the energy range from 100 eV to 1.5 keV
- Author
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Taglauer, E
- Published
- 1973
274. Comparison of Anti-SARS-CoV-2-Specific Antibody Signatures in Maternal and Infant Blood after COVID-19 Infection versus COVID-19 Vaccination during Pregnancy.
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Sabharwal V, Taglauer E, Demos R, Snyder-Cappione J, Shaik-Dasthagirisaheb YB, Parker-Kelleher S, Hunnewell J, Boateng J, Clarke K, Yuen R, Barnett ED, Wachman EM, and Yarrington CD
- Subjects
- Humans, Pregnancy, Female, Adult, Infant, Newborn, Immunoglobulin A blood, Fetal Blood immunology, Immunoglobulin M blood, Vaccination, Coronavirus Nucleocapsid Proteins immunology, COVID-19 prevention & control, COVID-19 immunology, COVID-19 Vaccines immunology, COVID-19 Vaccines administration & dosage, Antibodies, Viral blood, SARS-CoV-2 immunology, Pregnancy Complications, Infectious immunology, Pregnancy Complications, Infectious prevention & control, Pregnancy Complications, Infectious blood, Immunoglobulin G blood, Spike Glycoprotein, Coronavirus immunology
- Abstract
Objective: The Advisory Committee on Immunization Practices and The American College of Obstetricians and Gynecologists recommend coronavirus disease 2019 (COVID-19) vaccine for pregnant persons to prevent severe illness and death. The objective was to examine levels of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG, IgM, and IgA against spike protein receptor binding domain (RBD) and nucleocapsid protein (NCP) in maternal and infant/cord blood at delivery after COVID 19 vaccination compared with SARS-CoV-2 infection at in mother-infant dyads at specified time points., Study Design: Mothers with SARS-CoV-2 infection ( n = 31) or COVID-19 vaccination ( n = 25) during pregnancy were enrolled between July 2020 and November 2021. Samples were collected at delivery and IgG, IgM, and IgA to RBD of spike and NCPs compared in the infected and vaccinated groups. Timing of infection/vaccination prior to delivery and correlation with antibody levels was performed., Results: The majority of participants received vaccination within 90 days of delivery and over half received the Pfizer BioNTech vaccine. There were no significant correlations between antibody levels and timing of infection or vaccination. Infant IgG levels to the RBD domain of spike protein were higher in the vaccinated group ( n = 25) as compared with the infants born to mothers with infection ( n = 31). Vaccination against COVID-19 during pregnancy was associated with detectable maternal and infant anti-RBD IgG levels at delivery irrespective of the timing of vaccination., Conclusion: Timing of vaccination had no correlation to the antibody levels suggesting that the timing of maternal vaccination in the cohort did not matter. There was no IgM detected in infants from vaccinated mothers. Infants from vaccinated mothers had robust IgG titers to RBD, which have a lasting protective effect in infants., Key Points: · COVID-19 vaccination during pregnancy had detectable antibody.. · No correlation between antibody levels and timing of vaccination.. · Infants from vaccinated mothers had robust IgG titers to RBD.., Competing Interests: None declared., (Thieme. All rights reserved.)
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- 2024
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275. Cytokine levels in maternal and infant blood after COVID-19 vaccination during pregnancy in comparison with unvaccinated controls.
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Sabharwal V, Demos R, Snyder-Cappione J, Parker SE, Shaik-Dasthagirisaheb Y, Hunnewell J, Boateng J, Clarke K, Yuen R, Barnett E, Yarrington C, Taglauer E, and Wachman EM
- Subjects
- Pregnancy, Female, Infant, Humans, COVID-19 Vaccines, Prospective Studies, SARS-CoV-2, Vaccination, Cytokines, COVID-19 prevention & control
- Abstract
The objective of this study was to compare maternal and infant cytokine profiles at delivery among those vaccinated against SARS-CoV-2 during pregnancy to unvaccinated controls. Mother-infant dyads were enrolled in this prospective cohort study, and maternal blood and infant and/or cord blood collected. Samples were analyzed utilizing a LEGENDplex 13-plex human anti-viral response cytokine panel. Maternal IP-10 and IFN-λ2/3 were lower in the vaccinated cohort. In the infants, levels were lower for IL-1β, IFN-λ2/3, and GM-CSF, and higher for IFN-λ1 in the vaccinated cohort. Vaccination against SARS-CoV-2 during pregnancy did not lead to elevations in cytokines in mothers or infants., Competing Interests: Declaration of Interest None., (Copyright © 2023 Elsevier B.V. All rights reserved.)
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- 2023
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276. SARS-CoV-2 in infant urine and fecal samples after in utero COVID-19 exposure.
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Boateng JO, Wachman EM, Turcinovic J, Devera J, Jain M, Jean-Sicard S, Woodard E, Cruikshank A, Sinha B, Bartolome R, Barnett ED, Parker MG, Yarrington C, Connor JH, Taglauer E, and Sabharwal V
- Subjects
- Adult, Feces, Female, Humans, Infant, Infectious Disease Transmission, Vertical, Pregnancy, RNA, Viral, RNA-Directed DNA Polymerase, SARS-CoV-2, COVID-19, Pregnancy Complications, Infectious diagnosis, Pregnancy Complications, Infectious epidemiology
- Abstract
Background: Coronavirus disease 2019 (COVID-19) is a pandemic that has and will continue to affect many pregnant women. Knowledge regarding the risk of vertical transmission is limited. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) real-time reverse transcriptase-polymerase chain reaction (RT-PCR) of nasopharyngeal swabs typically have been used to confirm the diagnosis among infants, but whether the virus can be detected in other biological specimens, and therefore potentially transmitted in other ways, is unknown. Positive SARS-CoV-2 RT-PCR has been reported from feces and urine from adult patients. We hypothesize that the presence of SARS-CoV-2 in infant urine and fecal samples after prenatal COVID-19 exposure is low., Methods: We examined the presence of SARS-CoV-2 RNA using RT-PCR in urine and fecal samples among 42 infants born to SARS-CoV-2-infected mothers during different stages of pregnancy., Results: A urine sample was collected from 39 of 42 infants and fecal samples from all 42 infants shortly after birth. Although the majority of the women had the symptomatic disease (85.6%), we were unable to detect the presence of SARS-CoV-2 virus from any infant urine or fecal samples., Conclusions: SARS-CoV-2 was not detected in infant urine or feces after maternal infection during pregnancy, providing further evidence for low rates of perinatal transmission., Impact: SARS-CoV-2 was not detected in the urine or feces of infants of mothers with COVID-19 during various time points in pregnancy. This study provides further evidence for low rates of perinatal transmission of SARS-CoV-2. Results help to provide guidance on perinatal care practices for infants exposed to COVID-19 in utero., (© 2021. The Author(s), under exclusive licence to the International Pediatric Research Foundation, Inc.)
- Published
- 2022
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277. Intratracheal transplantation of trophoblast stem cells attenuates acute lung injury in mice.
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Han J, Li G, Hou M, Ng J, Kwon MY, Xiong K, Liang X, Taglauer E, Shi Y, Mitsialis SA, Kourembanas S, El-Chemaly S, Lederer JA, Rosas IO, Perrella MA, and Liu X
- Subjects
- Alveolar Epithelial Cells, Animals, Bronchoalveolar Lavage Fluid, Lipopolysaccharides, Lung, Mice, Mice, Inbred C57BL, Stem Cells, Acute Lung Injury chemically induced, Acute Lung Injury therapy, Trophoblasts
- Abstract
Background: Acute lung injury (ALI) is a common lung disorder that affects millions of people every year. The infiltration of inflammatory cells into the lungs and death of the alveolar epithelial cells are key factors to trigger a pathological cascade. Trophoblast stem cells (TSCs) are immune privileged, and demonstrate the capability of self-renewal and multipotency with differentiation into three germ layers. We hypothesized that intratracheal transplantation of TSCs may alleviate ALI., Methods: ALI was induced by intratracheal delivery of bleomycin (BLM) in mice. After exposure to BLM, pre-labeled TSCs or fibroblasts (FBs) were intratracheally administered into the lungs. Analyses of the lungs were performed for inflammatory infiltrates, cell apoptosis, and engraftment of TSCs. Pro-inflammatory cytokines/chemokines of lung tissue and in bronchoalveolar lavage fluid (BALF) were also assessed., Results: The lungs displayed a reduction in cellularity, with decreased CD45
+ cells, and less thickening of the alveolar walls in ALI mice that received TSCs compared with ALI mice receiving PBS or FBs. TSCs decreased infiltration of neutrophils and macrophages, and the expression of interleukin (IL) 6, monocyte chemoattractant protein-1 (MCP-1) and keratinocyte-derived chemokine (KC) in the injured lungs. The levels of inflammatory cytokines in BALF, particularly IL-6, were decreased in ALI mice receiving TSCs, compared to ALI mice that received PBS or FBs. TSCs also significantly reduced BLM-induced apoptosis of alveolar epithelial cells in vitro and in vivo. Transplanted TSCs integrated into the alveolar walls and expressed aquaporin 5 and prosurfactant protein C, markers for alveolar epithelial type I and II cells, respectively., Conclusion: Intratracheal transplantation of TSCs into the lungs of mice after acute exposure to BLM reduced pulmonary inflammation and cell death. Furthermore, TSCs engrafted into the alveolar walls to form alveolar epithelial type I and II cells. These data support the use of TSCs for the treatment of ALI., (© 2021. The Author(s).)- Published
- 2021
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278. Mesenchymal Stromal Cell-Derived Extracellular Vesicles Restore Thymic Architecture and T Cell Function Disrupted by Neonatal Hyperoxia.
- Author
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Reis M, Willis GR, Fernandez-Gonzalez A, Yeung V, Taglauer E, Magaletta M, Parsons T, Derr A, Liu X, Maehr R, Kourembanas S, and Mitsialis SA
- Subjects
- Animals, Animals, Newborn, Extracellular Vesicles metabolism, Heterografts, Humans, Mice, Umbilical Cord, Extracellular Vesicles transplantation, Hyperoxia complications, Mesenchymal Stem Cells metabolism, T-Lymphocytes immunology, T-Lymphocytes pathology, Thymus Gland immunology, Thymus Gland pathology
- Abstract
Treating premature infants with high oxygen is a routine intervention in the context of neonatal intensive care. Unfortunately, the increase in survival rates is associated with various detrimental sequalae of hyperoxia exposure, most notably bronchopulmonary dysplasia (BPD), a disease of disrupted lung development. The effects of high oxygen exposure on other developing organs of the infant, as well as the possible impact such disrupted development may have on later life remain poorly understood. Using a neonatal mouse model to investigate the effects of hyperoxia on the immature immune system we observed a dramatic involution of the thymic medulla, and this lesion was associated with disrupted FoxP3
+ regulatory T cell generation and T cell autoreactivity. Significantly, administration of mesenchymal stromal cell-derived extracellular vesicles (MEx) restored thymic medullary architecture and physiological thymocyte profiles. Using single cell transcriptomics, we further demonstrated preferential impact of MEx treatment on the thymic medullary antigen presentation axis, as evidenced by enrichment of antigen presentation and antioxidative-stress related genes in dendritic cells (DCs) and medullary epithelial cells (mTECs). Our study demonstrates that MEx treatment represents a promising restorative therapeutic approach for oxygen-induced thymic injury, thus promoting normal development of both central tolerance and adaptive immunity., Competing Interests: SK and SAM are named inventors on intellectual property licensed by Boston Children’s Hospital to United Therapeutics Corp. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Reis, Willis, Fernandez-Gonzalez, Yeung, Taglauer, Magaletta, Parsons, Derr, Liu, Maehr, Kourembanas and Mitsialis.)- Published
- 2021
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279. Differential Expression of Rab5 and Rab7 Small GTPase Proteins in Placental Tissues From Pregnancies Affected by Maternal Coronavirus Disease 2019.
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Benarroch Y, Juttukonda L, Sabharwal V, Boateng J, Khan AR, Yarrington C, Wachman EM, and Taglauer E
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- Female, Humans, Pregnancy, Pregnancy Complications, Infectious virology, SARS-CoV-2, rab7 GTP-Binding Proteins, COVID-19 metabolism, Placenta metabolism, Pregnancy Complications, Infectious metabolism, Trophoblasts metabolism, rab GTP-Binding Proteins metabolism, rab5 GTP-Binding Proteins metabolism
- Abstract
Purpose: The majority of pregnancies affected by maternal coronavirus disease 2019 (COVID-19) do not result in fetal transmission. However, several studies have identified parenchymal changes in their placental tissues, suggesting a placental response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the maternal-fetal interface. Although many COVID-19 placental studies have focused on the expression of the canonical SARS-CoV-2 entry proteins angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2, further characterization of subcellular molecules involved in viral trafficking have not yet been investigated in these tissues. Of interest are Rab proteins, a family of small GTPase proteins that direct intracellular transport between different endocytic organelles. Rab5 and Rab7 in particular have previously been implicated in HIV and cytomegalovirus invasion of placental trophoblast cells in vitro; the localization of these molecules has not been fully characterized within the human maternal-fetal interface, however, or within placental tissues from SARS-CoV-2-infected pregnancies., Methods: Using fluorescent immunohistochemistry, Rab5 and Rab7 placental localization and comparative fluorescence intensity were explored in a cohort of placental tissues from pregnancies affected by maternal COVID-19 disease (COVID, n = 15) compared with contemporary control subjects (Control, n = 10). Fluorescence intensity was quantified by using corrected total cell fluorescence values., Findings: Within placental villi, Rab5 was consistently localized in syncytiotrophoblast and cytotrophoblast cells. Rab5 had significantly higher mean (SEM) fluorescence intensity in the COVID cohort (Control, 1.96 [0.16]; COVID, 2.62 [0.09]; P = 0.0014). In contrast, although Rab7 was also localized within placental villous syncytiotrophoblast and cytotrophoblast cells, mean (SEM) Rab7 fluorescence intensity was significantly downregulated in COVID vs Control placentas (Control, 35.9 [4.1]; COVID, 20.1 [0.52]; P = 0.0001)., Implications: This differential expression of Rab5 and Rab7 suggests that placental endocytic pathways may be altered at the maternal-fetal interface in pregnancies affected by maternal SARS-CoV-2 infection. As key molecules governing intracellular vesicle transport, including viral trafficking, Rab GTPase proteins may be of interest for ongoing studies examining placental responses to COVID-19 in pregnancy., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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280. Perinatal Hypoxia-Inducible Factor Stabilization Preserves Lung Alveolar and Vascular Growth in Experimental Bronchopulmonary Dysplasia.
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Hirsch K, Taglauer E, Seedorf G, Callahan C, Mandell E, White CW, Kourembanas S, and Abman SH
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- Amino Acids, Dicarboxylic pharmacology, Animals, Animals, Newborn, Blotting, Western, Bronchopulmonary Dysplasia metabolism, Bronchopulmonary Dysplasia pathology, Disease Models, Animal, Endotoxins adverse effects, Endotoxins pharmacology, Female, Hypoxia-Inducible Factor 1 drug effects, Immunohistochemistry, In Vitro Techniques, Injections, Intralesional, Lung embryology, Pregnancy, Prenatal Care, Pulmonary Alveoli drug effects, Pulmonary Alveoli growth & development, Pulmonary Circulation drug effects, Random Allocation, Rats, Rats, Sprague-Dawley, Reference Values, Respiratory Function Tests, Tissue Culture Techniques, Bronchopulmonary Dysplasia drug therapy, Hypoxia-Inducible Factor 1 metabolism, Lung drug effects, Peptide PHI pharmacology, Pregnancy, Animal
- Abstract
Rationale: Antenatal inflammation with placental dysfunction is strongly associated with high bronchopulmonary dysplasia (BPD) risk in preterm infants. Whether antenatal or postnatal HIF (hypoxia-inducible factor) augmentation can preserve lung structure and function and prevent pulmonary hypertension after intrauterine inflammation is controversial. Objectives: To determine whether antenatal or postnatal prolyl-hydroxylase inhibitor (PHi) therapy increases lung HIF expression, preserves lung growth and function, and prevents pulmonary hypertension in a rat model of chorioamnionitis-induced BPD caused by antenatal inflammation. Methods: Endotoxin (ETX) was administered to pregnant rats by intraamniotic injection at Embryonic Day 20, and pups were delivered by cesarean section at Embryonic Day 22. Selective PHi drugs, dimethyloxalylglycine or GSK360A, were administered into the amniotic space at Embryonic Day 20 or after birth by intraperitoneal injection for 2 weeks. Placentas and lung tissue were collected at birth for morphometric and Western blot measurements of HIF-1a, HIF-2a, VEGF (vascular endothelial growth factor), and eNOS (endothelial nitric oxide synthase) protein contents. At Day 14, lung function was assessed, and tissues were harvested to determine alveolarization by radial alveolar counts, pulmonary vessel density, and right ventricle hypertrophy (RVH). Measurements and Main Results: Antenatal PHi therapy preserves lung alveolar and vascular growth and lung function and prevents RVH after intrauterine ETX exposure. Antenatal administration of PHi markedly upregulates lung HIF-1a, HIF-2a, VEGF, and eNOS expression after ETX exposure. Conclusions: HIF augmentation improves lung structure and function, prevents RVH, and improves placental structure following antenatal ETX exposure. We speculate that antenatal or postnatal PHi therapy may provide novel strategies to prevent BPD due to antenatal inflammation.
- Published
- 2020
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281. Consistent localization of SARS-CoV-2 spike glycoprotein and ACE2 over TMPRSS2 predominance in placental villi of 15 COVID-19 positive maternal-fetal dyads.
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Taglauer E, Benarroch Y, Rop K, Barnett E, Sabharwal V, Yarrington C, and Wachman EM
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- Angiotensin-Converting Enzyme 2, COVID-19, Female, Fetus, Fluorescent Antibody Technique methods, Humans, Infectious Disease Transmission, Vertical, Placenta chemistry, Pregnancy, Pregnancy Complications, Infectious virology, Receptors, Virus analysis, SARS-CoV-2, Trophoblasts chemistry, Betacoronavirus chemistry, Chorionic Villi chemistry, Coronavirus Infections, Pandemics, Peptidyl-Dipeptidase A analysis, Pneumonia, Viral, Serine Endopeptidases analysis, Spike Glycoprotein, Coronavirus analysis
- Abstract
Introduction: While the COVID-19 pandemic continues to have a significant global health impact, rates of maternal to infant vertical transmission remain low (<5%). Parenchymal changes of placentas from COVID-19 infected mothers have been reported by several groups, but the localization and relative abundance of SARS-CoV-2 viral proteins and cellular entry machinery has not been fully characterized within larger placental tissue cohorts., Methods: An extended placental tissue cohort including samples from 15 COVID-19 positive maternal-fetal dyads (with n = 5 cases with evidence of fetal transmission) in comparison with 10 contemporary COVID-19 negative controls. Using comparative immunofluorescence, we examined the localization and relative tissue abundance of SARS-CoV2 spike glycoprotein (CoV2 SP) along with the co-localization of two SARS-CoV2 viral entry proteins angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2)., Results/conclusions: CoV2 SP was present within the villous placenta in COVID-19 positive pregnancies with and without evidence of fetal transmission. We further identified the predominance of ACE2 expression in comparison with TMPRSS2. Importantly, both CoV2 SP and ACE2 expression consistently localized primarily within the outer syncytiotrophoblast layer placental villi, a key physiologic interface between mother and fetus. Overall this study provides an important basis for the ongoing evaluation of SARS-CoV-2 physiology in pregnancy and highlights the importance of the placenta as a key source of primary human tissue for ongoing diagnostic and therapeutic research efforts to reduce the global burden of COVID-19., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2020
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282. Recent advances in antenatal factors predisposing to bronchopulmonary dysplasia.
- Author
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Taglauer E, Abman SH, and Keller RL
- Subjects
- Amniotic Fluid, Bronchopulmonary Dysplasia physiopathology, Causality, Female, Humans, Hypertension, Pulmonary physiopathology, Infant, Extremely Premature, Infant, Newborn, Infant, Premature, Infant, Very Low Birth Weight, Pregnancy, Premature Birth, United States epidemiology, Bronchopulmonary Dysplasia epidemiology, Hypertension, Pulmonary epidemiology, Lung pathology, Oxidative Stress physiology, Placenta Growth Factor metabolism, Vascular Endothelial Growth Factor A metabolism
- Abstract
Bronchopulmonary dysplasia (BPD) remains a major cause of late morbidities and death after preterm birth. BPD is characterized by an arrest of vascular and alveolar growth and high risk for pulmonary hypertension; yet mechanisms contributing to its pathogenesis and early strategies to prevent BPD are poorly understood. Strong epidemiologic studies have shown that the "new BPD" reflects the long-lasting impact of antenatal factors on lung development, partly due to placental dysfunction, as reflected in recent data from animal models. Improved understanding of mechanisms through which antenatal stress alters placental function and contributes to BPD may lead to preventive therapies., (Copyright © 2018. Published by Elsevier Inc.)
- Published
- 2018
- Full Text
- View/download PDF
283. Review: cell-free fetal DNA in the maternal circulation as an indication of placental health and disease.
- Author
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Taglauer ES, Wilkins-Haug L, and Bianchi DW
- Subjects
- Apoptosis, Female, Humans, Mosaicism, Pregnancy, Prenatal Care, DNA blood, Placenta physiology, Placenta Diseases blood
- Abstract
In human pregnancy, the constant turnover of villous trophoblast results in extrusion of apoptotic material into the maternal circulation. This material includes cell-free (cf) DNA, which is commonly referred to as "fetal", but is actually derived from the placenta. As the release of cf DNA is closely tied to placental morphogenesis, conditions associated with abnormal placentation, such as preeclampsia, are associated with high DNA levels in the blood of pregnant women. Over the past five years, the development and commercial availability of techniques of massively parallel DNA sequencing have facilitated noninvasive prenatal testing (NIPT) for fetal trisomies 13, 18, and 21. Clinical experience accrued over the past two years has highlighted the importance of the fetal fraction (ff) in cf DNA analysis. The ff is the amount of cell-free fetal DNA in a given sample divided by the total amount of cell-free DNA. At any gestational age, ff has a bell-shaped distribution that peaks between 10 and 20% at 10-21 weeks. ff is affected by maternal body mass index, gestational age, fetal aneuploidy, and whether the gestation is a singleton or multiple. In approximately 0.1% of clinical cases, the NIPT result and a subsequent diagnostic karyotype are discordant; confined placental mosaicism has been increasingly reported as an underlying biologic explanation. Cell-free fetal DNA is a new biomarker that can provide information about the placenta and potentially be used to predict clinical problems. Knowledge gaps still exist with regard to what affects production, metabolism, and clearance of feto-placental DNA., (Copyright © 2013 IFPA and Elsevier Ltd. All rights reserved.)
- Published
- 2014
- Full Text
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284. Chorionic plate expression patterns of the maspin tumor suppressor protein in preeclamptic and egg donor placentas.
- Author
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Taglauer ES, Gundogan F, Johnson KL, Scherjon SA, and Bianchi DW
- Subjects
- Female, Fertilization in Vitro, Humans, Oocyte Donation, Pre-Eclampsia metabolism, Pregnancy immunology, Chorion metabolism, Placenta metabolism, Pre-Eclampsia physiopathology, Serpins biosynthesis
- Abstract
Maspin is a serine protease inhibitor involved in regulating human placental trophoblast cell migration. Maspin has not been studied in preeclampsia (PE) or relative to the maternal-fetal immunological relationship, both of which may involve altered trophoblast migration. We examined maspin expression in placentas from in vitro fertilization (IVF) and egg donor (ED) pregnancies with and without PE. Exclusive to the chorionic plate, the number of maspin-positive extravillous trophoblasts was significantly decreased in IVF-PE vs. IVF (p = 0.005) and ED vs. IVF (p = 0.013). These data suggest maspin expression may be influenced by PE and/or the immunological dynamics of pregnancy., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
285. Crystal effects in the neutralization of He+ ions in the low energy ion scattering regime.
- Author
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Primetzhofer D, Markin SN, Juaristi JI, Taglauer E, and Bauer P
- Abstract
Investigating possible crystal effects in ion scattering from elemental surfaces, measurements of the positive ion fraction P+ are reported for He+ ions scattered from single and polycrystalline Cu surfaces. In the Auger neutralization regime, the ion yield is determined by scattering from the outermost atomic layer. For Cu(110) P+ exceeds that for polycrystalline Cu by up to a factor of 2.5, thus exhibiting a strong crystal effect. It is much less pronounced at higher energies, i.e., in the reionization regime. However, there a completely different angular dependence of the ion yield is observed for poly- and single crystals, due to massive subsurface contributions in nonchanneling directions.
- Published
- 2008
- Full Text
- View/download PDF
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