1
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di Vacri ML, Arnquist IJ, Back HO, Bliss M, Bronikowski M, Edwards E, Hackett BR, Hoppe EW, Lyons SM, Rocco ND, Rosero R, Seifert A, Swindle A, Yeh M. Identification of background limitations to ultra-sensitive LSC counting through ICP-MS assay of LSC cocktails. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08591-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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2
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Huber A, Seifert A. Retrospective feelings of loneliness during the COVID-19 pandemic among residents of long-term care facilities. Aging Health Res 2022; 2:100053. [PMID: 35018357 PMCID: PMC8739825 DOI: 10.1016/j.ahr.2022.100053] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 11/25/2022] Open
Abstract
The novel coronavirus disease (COVID-19) has had an incisive effect on residents living in long-term care facilities (LTCFs). Local governments have introduced restrictive measures because of the danger posed by this virus. One increasing negative effect of these implementations among residents living in LTCFs is their subjective feelings of loneliness. This study assumed that these measures weighed heavily particularly on residents living in LTCFs, as this group of older people could not decide for themselves whether or how they should be implemented. Thus, this study investigated the retrospectively reported subjective loneliness of residents living in LTCFs. On a large-scale Swiss survey (N = 828; mean age: 87.78, 75% female), residents of 22 LTCFs filled out a questionnaire on their subjective feelings of loneliness during the pandemic. The retrospective loneliness scores of the residents living in LTCFs were found to exceed those reported in other studies focusing on community-dwelling older people. Multivariate regression analyses showed that females, individuals with lower values of joy in life and life satisfaction, and individuals who were not satisfied with the manner in which their care home coped with the COVID-19 measures significantly felt lonelier. Therefore, the subjective feelings of loneliness of residents in LTCFs should be monitored very carefully. As the measures have still not been completely lifted, residents of LTCFs are assumed to still experience social isolation and be at high risk of encountering prolonged feelings of loneliness, which can be detrimental to their mental health and well-being.
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Affiliation(s)
- A Huber
- Center for Gerontology, University of Zurich, Zurich, Switzerland
| | - A Seifert
- Center for Gerontology, University of Zurich, Zurich, Switzerland
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3
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Olaetxea I, Lopez E, Valero A, Seifert A. Determination of physiological lactate and pH by Raman spectroscopy. Annu Int Conf IEEE Eng Med Biol Soc 2020; 2019:475-481. [PMID: 31945941 DOI: 10.1109/embc.2019.8856471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lactate and pH values in human blood are important physiological parameters that can reflect serious pathological states as sepsis or hypoxia. In this study we demonstrate that we can determine lactate and pH values from blood samples by Raman spectroscopy combined with multivariate analysis at medically relevant resolution and reliability. The method prepares the base for new real-time in vivo analytics for a number of pathological cases and physiological control in competitive sports. We demonstrate the capability to resolve pH variations of 0.04 and lactate concentrations of 0.20 mM ex vivo.
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4
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Johnson C, Aalseth CE, Alexander TR, Bowyer TW, Chipman V, Day AR, Drellack S, Fast JE, Fritz BG, Hayes JC, Huckins-Gang HE, Humble P, Kirkham RR, Lowrey JD, Mace EK, Mayer MF, McIntyre JI, Milbrath BD, Panisko ME, Paul MJ, Obi CM, Okagawa RK, Olsen KB, Ripplinger MD, Seifert A, Suarez R, Thomle J, Townsend MJ, Woods VT, Zhong L. Migration of noble gas tracers at the site of an underground nuclear explosion at the Nevada National Security Site. J Environ Radioact 2019; 208-209:106047. [PMID: 31526956 DOI: 10.1016/j.jenvrad.2019.106047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 06/10/2023]
Abstract
As part of an underground gas migration study, two radioactive noble gases (37Ar and 127Xe) and two stable tracer gases (SF6 and PFDMCH) were injected into a historic nuclear explosion test chimney and allowed to migrate naturally. The purpose of this experiment was to provide a bounding case (natural transport) for the flow of radioactive noble gases following an underground nuclear explosion. To accomplish this, soil gas samples were collected from a series of boreholes and a range of depths from the shallow subsurface (3 m) to deeper levels (~160 m) over a period of eleven months. These samples have provided insights into the development and evolution of the subsurface plume and constrained the relative migration rates of the radioactive and stable gas species in the case when the driving pressure from the cavity is low. Analysis of the samples concluded that the stable tracer SF6 was consistently enriched in the subsurface samples relative to the radiotracer 127Xe, but the ratios of SF6 and 37Ar remained similar throughout the samples.
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Affiliation(s)
- C Johnson
- Pacific Northwest National Laboratory, Richland, WA, USA.
| | - C E Aalseth
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - T R Alexander
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - T W Bowyer
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - V Chipman
- Mission Support and Test Services LLC, Las Vegas, NV, USA
| | - A R Day
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - S Drellack
- Mission Support and Test Services LLC, Las Vegas, NV, USA
| | - J E Fast
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - B G Fritz
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - J C Hayes
- Pacific Northwest National Laboratory, Richland, WA, USA
| | | | - P Humble
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - R R Kirkham
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - J D Lowrey
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - E K Mace
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - M F Mayer
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - J I McIntyre
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - B D Milbrath
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - M E Panisko
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - M J Paul
- Sandia National Laboratories, Albuquerque, NM, USA
| | - C M Obi
- Mission Support and Test Services LLC, Las Vegas, NV, USA
| | - R K Okagawa
- Mission Support and Test Services LLC, Las Vegas, NV, USA
| | - K B Olsen
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - M D Ripplinger
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - A Seifert
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - R Suarez
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - J Thomle
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - M J Townsend
- Mission Support and Test Services LLC, Las Vegas, NV, USA
| | - V T Woods
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - L Zhong
- Pacific Northwest National Laboratory, Richland, WA, USA
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6
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Uhlig D, Spange S, Seifert A, Nagel K, Anders S, Kroll L, Stoll R, Thielbeer F, Müller P, Schreiter K. Design of nanostructured hybrid materials: twin polymerization of urethane-based twin prepolymers. RSC Adv 2018; 8:31673-31681. [PMID: 35548201 PMCID: PMC9085902 DOI: 10.1039/c8ra05310c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 09/04/2018] [Indexed: 11/30/2022] Open
Abstract
Organic–inorganic hybrid materials with urethane functionalities were obtained by simultaneous twin polymerization of twin prepolymers in combination with the ideal twin monomer 2,2′-spirobi[4H-1,3,2-benzodioxasiline]. The twin prepolymers consist of a urethane-based prepolymer with reactive terminal groups which can react during the twin polymerization process. Nanostructured hybrid materials with integrated dialkylsiloxane crosslinked urethane structures, phenolic resin and SiO2 are obtained in a one pot process. The effects of the polymerization temperature as well as those of various catalysts and reagent ratios on the polymerization behavior were investigated. The molecular structures of the obtained materials were determined by 13C- and 29Si-{1H}-CP-MAS NMR spectroscopies. HAADF-STEM-measurements were performed to prove the distribution of silicon in the hybrid material. Organic–inorganic hybrid materials with urethane functionalities were obtained by simultaneous twin polymerization of twin prepolymers in combination with the twin monomer 2,2′-spirobi[4H-1,3,2-benzodioxasiline].![]()
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Affiliation(s)
- D. Uhlig
- Department of Polymer Chemistry
- Chemnitz University of Technology
- Faculty of Natural Science
- D-09107 Chemnitz
- Germany
| | - S. Spange
- Department of Polymer Chemistry
- Chemnitz University of Technology
- Faculty of Natural Science
- D-09107 Chemnitz
- Germany
| | - A. Seifert
- Department of Polymer Chemistry
- Chemnitz University of Technology
- Faculty of Natural Science
- D-09107 Chemnitz
- Germany
| | - K. Nagel
- Department of Polymer Chemistry
- Chemnitz University of Technology
- Faculty of Natural Science
- D-09107 Chemnitz
- Germany
| | - S. Anders
- Department of Lightweight Structures and Polymer Technology
- Chemnitz University of Technology
- Faculty of Mechanical Engineering
- D-09107 Chemnitz
- Germany
| | - L. Kroll
- Department of Lightweight Structures and Polymer Technology
- Chemnitz University of Technology
- Faculty of Mechanical Engineering
- D-09107 Chemnitz
- Germany
| | | | | | | | - K. Schreiter
- Department of Polymer Chemistry
- Chemnitz University of Technology
- Faculty of Natural Science
- D-09107 Chemnitz
- Germany
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7
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Abstract
Foamed organic/silica hybrid materials are synthesized via cationic polymerization of organic carbonates with twin monomers. They are converted into hierarchically structured carbon and silica.
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Affiliation(s)
- L. Wöckel
- Polymer Chemistry
- Chemnitz University of Technology
- 09107 Chemnitz
- Germany
| | - T. Windberg
- Polymer Chemistry
- Chemnitz University of Technology
- 09107 Chemnitz
- Germany
| | - R. John
- Polymer Chemistry
- Chemnitz University of Technology
- 09107 Chemnitz
- Germany
| | - A. Seifert
- Polymer Chemistry
- Chemnitz University of Technology
- 09107 Chemnitz
- Germany
| | - S. Spange
- Polymer Chemistry
- Chemnitz University of Technology
- 09107 Chemnitz
- Germany
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8
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Nagel K, Kaßner L, Seifert A, Grützner RE, Cox G, Spange S. Ternary composites by an in situ hydrolytic polymerization process. RSC Adv 2018; 8:14713-14721. [PMID: 35540740 PMCID: PMC9079966 DOI: 10.1039/c8ra02402b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 04/02/2018] [Indexed: 12/02/2022] Open
Abstract
Polyamide 6/modified silica composite materials have been prepared by a coupled polymerization procedure. For this purpose, the three-component-system we presented in a previous publication, consisting of ε-aminocaproic acid (ε-ACA), ε-caprolactam (ε-CL), and 1,1′,1′′,1′′′-silanetetrayltetrakis-(azepan-2-one) (Si(ε-CL)4), has been combined with other silicon monomers with one or two methyl groups (MeSi(ε-CL)3 and Me2Si(ε-CL)2). The simultaneous polymerization of ε-CL and silicon monomers leads to the in situ formation of silica/polysiloxane particles and the surrounding polyamide 6 matrix in one step. Moreover, 3-aminopropyltriethoxysilane has been added to the three-component-system to achieve covalent bonding between organic and inorganic phases and to inhibit agglomeration of the silica particles. Chemical structures and morphologies of the composites have been investigated by solid-state NMR and FTIR spectroscopy as well as electron microscopy and SEC measurements. Structural effects on thermal properties have been studied by DSC and TGA measurements. Polyamide 6/silica/polysiloxane composites have been prepared in a one-step process using lactam-substituted silicon monomers.![]()
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Affiliation(s)
- K. Nagel
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | - L. Kaßner
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | - A. Seifert
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | | | - G. Cox
- BASF SE
- 67056 Ludwigshafen am Rhein
- Germany
| | - S. Spange
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
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9
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McIntyre JI, Aalseth CE, Alexander TR, Back HO, Bellgraph BJ, Bowyer TW, Chipman V, Cooper MW, Day AR, Drellack S, Foxe MP, Fritz BG, Hayes JC, Humble P, Keillor ME, Kirkham RR, Krogstad EJ, Lowrey JD, Mace EK, Mayer MF, Milbrath BD, Misner A, Morley SM, Panisko ME, Olsen KB, Ripplinger MD, Seifert A, Suarez R. Measurements of Argon-39 at the U20az underground nuclear explosion site. J Environ Radioact 2017; 178-179:28-35. [PMID: 28755564 DOI: 10.1016/j.jenvrad.2017.07.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 06/07/2023]
Abstract
Pacific Northwest National Laboratory reports on the detection of 39Ar at the location of an underground nuclear explosion on the Nevada Nuclear Security Site. The presence of 39Ar was not anticipated at the outset of the experimental campaign but results from this work demonstrated that it is present, along with 37Ar and 85Kr in the subsurface at the site of an underground nuclear explosion. Our analysis showed that by using state-of-the-art technology optimized for radioargon measurements, it was difficult to distinguish 39Ar from the fission product 85Kr. Proportional counters are currently used for high-sensitivity measurement of 37Ar and 39Ar. Physical and chemical separation processes are used to separate argon from air or soil gas, yielding pure argon with contaminant gases reduced to the parts-per-million level or below. However, even with purification at these levels, the beta decay signature of 85Kr can be mistaken for that of 39Ar, and the presence of either isotope increases the measurement background level for the measurement of 37Ar. Measured values for the 39Ar measured at the site ranged from 36,000 milli- Becquerel/standard-cubic-meter-of-air (mBq/SCM) for shallow bore holes to 997,000 mBq/SCM from the rubble chimney from the underground nuclear explosion.
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Affiliation(s)
- J I McIntyre
- Pacific Northwest National Laboratory, Richland, WA, USA.
| | - C E Aalseth
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - T R Alexander
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - H O Back
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - B J Bellgraph
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - T W Bowyer
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - V Chipman
- National Security Technologies, LLC (NSTec), North Las Vegas, NV, USA
| | - M W Cooper
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - A R Day
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - S Drellack
- National Security Technologies, LLC (NSTec), North Las Vegas, NV, USA
| | - M P Foxe
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - B G Fritz
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - J C Hayes
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - P Humble
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - M E Keillor
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - R R Kirkham
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - E J Krogstad
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - J D Lowrey
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - E K Mace
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - M F Mayer
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - B D Milbrath
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - A Misner
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - S M Morley
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - M E Panisko
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - K B Olsen
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - M D Ripplinger
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - A Seifert
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - R Suarez
- Pacific Northwest National Laboratory, Richland, WA, USA
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10
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Seifert A, Hartog CS, Zweigner J, Schummer W, Reinhart K. [Sepsis masquerading as delirium]. Anaesthesist 2017; 66:858-861. [PMID: 28887627 DOI: 10.1007/s00101-017-0361-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 08/16/2017] [Accepted: 08/18/2017] [Indexed: 10/18/2022]
Abstract
A previously healthy 60-year-old patient presented to the emergency department with severe headache, altered personality and fever. He was treated for bacterial meningitis with delirium of unknown cause but presumed to be due to alcohol withdrawal. Despite receiving the antibiotic therapy regimen recommended for bacterial meningitis the patient's condition rapidly deteriorated with profound delirium and tachypnea. The intensivist who was consulted immediately suspected sepsis-associated organ failure and admitted the patient to the intensive care unit (ICU). The blood culture was positive for Listeria. After 10 days the patient could be discharged from the ICU and ultimately recovered completely. In patients presenting with unexplained delirium or altered personality the suspicion of septic encephalopathy should always be considered. They should be admitted to the ICU and sepsis treatment should be initiated without delay.
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Affiliation(s)
- A Seifert
- Klinik für Anästhesie, Intensivmedizin und Schmerztherapie, Paracelsus-Klinik Zwickau, Zwickau, Deutschland
| | - C S Hartog
- Klinik für Anästhesie und Intensivtherapie, Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen, Universitätsklinikum Jena, Paul-Schneider-Str. 2, 07747, Jena, Deutschland.,Klinik Bavaria Kreischa, Kreischa, Deutschland
| | - J Zweigner
- Zentrale Krankenhaushygiene, Universitätsklinikum Köln, Köln, Deutschland
| | - W Schummer
- Klinik Bavaria Kreischa, Kreischa, Deutschland
| | - K Reinhart
- Klinik für Anästhesie und Intensivtherapie, Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen, Universitätsklinikum Jena, Paul-Schneider-Str. 2, 07747, Jena, Deutschland.
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11
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Keillor ME, Aalseth CE, Arnquist IJ, Eggemeyer TA, Fuller ES, Glasgow BD, Hoppe EW, Morley SM, Myers AW, Orrell JL, Overman CT, Seifert A, Shaff SM, Thommasson KS. Recent Bremsstrahlung-based assays of 210Pb in lead and comments on current availability of low-background lead in North America. Appl Radiat Isot 2017; 126:185-187. [PMID: 28318931 DOI: 10.1016/j.apradiso.2017.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 03/01/2017] [Accepted: 03/02/2017] [Indexed: 11/19/2022]
Abstract
Low-background lead for radiation measurement shielding is often assayed for 210Pb to ensure acceptable backgrounds. Samples of lead assayed with a germanium spectrometer calibrated for bremsstrahlung-based assay of 210Pb provide a view into the 210Pb content of commercial lead in the U.S. (other than stockpiled Doe Run lead). Results suggest that the loss of lead smelting in the U.S. has eliminated the traditional supply of "low background" lead (~30Bqkg-1), and indicate current commercial supplies contain roughly an order of magnitude higher 210Pb levels.
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Affiliation(s)
- Martin E Keillor
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA.
| | - C E Aalseth
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - I J Arnquist
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - T A Eggemeyer
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - E S Fuller
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - B D Glasgow
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - E W Hoppe
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - S M Morley
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - A W Myers
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - J L Orrell
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - C T Overman
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - A Seifert
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - S M Shaff
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - K S Thommasson
- Pacific Northwest National Laboratory, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
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12
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Williams R, Aalseth C, Brandenberger J, Day A, Finn E, Fuller E, Hoppe E, Humble P, Keillor M, Mace E, Myers A, Overman C, Panisko M, Seifert A, White S. Development of a low-level 39Ar calibration standard – Analysis by absolute gas counting measurements augmented with simulation. Appl Radiat Isot 2017; 126:243-248. [DOI: 10.1016/j.apradiso.2017.02.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/28/2016] [Accepted: 02/11/2017] [Indexed: 10/20/2022]
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13
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Seifert A, König R, Doh M. INTERNET DIFFUSION AMONG OLDER PERSONS IN EUROPE—A STATISTICAL ANALYSIS OF SHARE DATA. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.2747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- A. Seifert
- Center Center of Competence for Gerontology, University of Zurich, Zurich, Switzerland,
- URPP Dynamics of Healthy Aging / University of Zurich, Zurich, Switzerland,
| | - R. König
- Institute of Sociology, University of Zurich, Zurich, Switzerland,
| | - M. Doh
- Department of Psychological Ageing Research, Institute of Psychology, Heidelberg University, Heidelberg, Switzerland
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14
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Wöckel L, Seifert A, Mende C, Roth-Panke I, Kroll L, Spange S. Resin and carbon foam production by cationic step-growth polymerization of organic carbonates. Polym Chem 2017. [DOI: 10.1039/c6py01572g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acid induced step-growth polymerizations of bis(p-methoxybenzyl) carbonate (pMBC), bis(m-methoxybenzyl) carbonate (mMBC) and difurfuryl carbonate (DFC) have been performed to produce resin-foams, because controlled release of carbon dioxide takes place during polymerization of those organic carbonates.
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Affiliation(s)
- L. Wöckel
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | - A. Seifert
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | - C. Mende
- Department of Lightweight Structures and Polymer Technology
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | - I. Roth-Panke
- Department of Lightweight Structures and Polymer Technology
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | - L. Kroll
- Department of Lightweight Structures and Polymer Technology
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | - S. Spange
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
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15
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Blattmann M, Kretschmer S, Thiele S, Ataman C, Zappe H, Herkommer A, Seifert A. Bimodal endoscopic probe combining white-light microscopy and optical coherence tomography. Appl Opt 2016; 55:4261-4269. [PMID: 27411158 DOI: 10.1364/ao.55.004261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a novel bimodal endoscopic imaging probe that can simultaneously provide full-field white-light video microscopy and confocal optical coherence tomography (OCT) depth scans. The two modalities rely on spectrally separated optical paths that run partially in parallel through a micro-optical bench system, which has a cross-section of only 2 mm×2.76 mm and is realized via standard silicon micromachining techniques. With a numerical aperture of 0.061, the video modality has a resolution and field of view of 9.3 and 1240 μm×1080 μm, respectively. The resolution is limited by the pixel spacing of the coherent fiber bundle, which relays the acquired image from the distal to the proximal end. A custom-designed diffractive optical element placed within the video imaging path significantly improves the image contrast by up to 45% in the medium frequency range. The OCT modality is optimized for 830 nm center wavelength, and works in a confocal arrangement with an NA of 0.018. It provides single-point depth probing at the center of the video image with a lateral resolution of 20 μm. Through its compact footprint and enhanced functionality, the probe can provide depth-resolved guiding capability for existing laparoscopes and represents a major step toward a new class of multimodal endoscopic imaging probes.
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Mace EK, Aalseth CE, Day AR, Hoppe EW, Keillor ME, Moran JJ, Panisko ME, Seifert A, Tatishvili G, Williams RM. First results of a simultaneous measurement of tritium and (14)C in an ultra-low-background proportional counter for environmental sources of methane. J Environ Radioact 2016; 155-156:122-129. [PMID: 26990077 DOI: 10.1016/j.jenvrad.2016.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 02/01/2016] [Accepted: 02/01/2016] [Indexed: 06/05/2023]
Abstract
Simultaneous measurement of tritium and (14)C would provide an added tool for tracing organic compounds through environmental systems and is possible via beta energy spectroscopy of sample-derived methane in internal-source gas proportional counters. Since the mid-1960's atmospheric tritium and (14)C have fallen dramatically as the isotopic injections from aboveground nuclear testing have been diluted into the ocean and biosphere. In this work, the feasibility of simultaneous tritium and (14)C measurements via proportional counters is revisited in light of significant changes in both the atmospheric and biosphere isotopics and the development of new ultra-low-background gas proportional counting capabilities for small samples (roughly 50 cc methane). A Geant4 Monte Carlo model of a Pacific Northwest National Laboratory (PNNL) proportional counter response to tritium and (14)C is used to analyze small samples of two different methane sources to illustrate the range of applicability of contemporary simultaneous measurements and their limitations. Because the two methane sources examined were not sample size limited, we could compare the small-sample measurements performed at PNNL with analysis of larger samples performed at a commercial laboratory. These first results show that the dual-isotope simultaneous measurement is well matched for methane samples that are atmospheric or have an elevated source of tritium (i.e. landfill gas). However, for samples with low/modern tritium isotopics (rainwater), commercial separation and counting is a better fit.
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Affiliation(s)
- E K Mace
- Pacific Northwest National Laboratory, 902 Battelle Blvd, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA.
| | - C E Aalseth
- Pacific Northwest National Laboratory, 902 Battelle Blvd, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - A R Day
- Pacific Northwest National Laboratory, 902 Battelle Blvd, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - E W Hoppe
- Pacific Northwest National Laboratory, 902 Battelle Blvd, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - M E Keillor
- Pacific Northwest National Laboratory, 902 Battelle Blvd, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - J J Moran
- Pacific Northwest National Laboratory, 902 Battelle Blvd, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - M E Panisko
- Pacific Northwest National Laboratory, 902 Battelle Blvd, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - A Seifert
- Pacific Northwest National Laboratory, 902 Battelle Blvd, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - G Tatishvili
- Pacific Northwest National Laboratory, 902 Battelle Blvd, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
| | - R M Williams
- Pacific Northwest National Laboratory, 902 Battelle Blvd, P.O. Box 999, MSIN J4-65, Richland, WA 99352, USA
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17
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Ariunaa A, Bernhardt D, Beckmann M, Gebauer K, Hack N, Seifert A, Fischer R, Unz S, Narangerel J, Purevsuren B. Research on the thermal decomposition of Mongolian Baganuur lignite and Naryn sukhait bituminous coal. Mong J Chem 2016. [DOI: 10.5564/mjc.v16i0.665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The technical characteristics, elemental composition of the organic and mineral matters, ash melting behaviors and carbonization and gasification reactivities of coals from Baganuur and Naryn sukhait deposits were investigated. The results of proximate and ultimate analysis confirmed that the coal from Baganuur deposit can be graded as a low rank lignite B2 mark coal and Naryn sukhait coal is a bituminous G mark one. The carbonization and gasification experiments were performed using TGA apparatus and fixed bed quartz reactor. The data obtained with two experimental reactors showed that Baganuur lignite had lower thermal stability and much higher CO2 gasification reactivity at 950°C as compared to those for Naryn sukhait bituminous coal.Mongolian Journal of Chemistry 16 (42), 2015, 22-29
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18
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Williams R, Aalseth C, Bowyer T, Day A, Fuller E, Haas D, Hayes J, Hoppe E, Humble P, Keillor M, LaFerriere B, Mace E, McIntyre J, Miley H, Myers A, Orrell J, Overman C, Panisko M, Seifert A. Development of a low-level 37Ar calibration standard. Appl Radiat Isot 2016; 109:430-434. [DOI: 10.1016/j.apradiso.2015.12.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 12/04/2015] [Indexed: 10/22/2022]
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19
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Wussler D, Kiefer S, Haberstroh J, Kesseler N, Kubicki R, Ruh D, Heilmann C, Seifert A, Siepe M, Stiller B, Lang N. Evaluation of a Light Activated and Elastomeric Tissue Sealant for Vascular Surgery. Thorac Cardiovasc Surg 2016. [DOI: 10.1055/s-0036-1571949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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20
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Aalseth C, Humble P, Mace E, Orrell J, Seifert A, Williams R. Shielding concepts for low-background proportional counter arrays in surface laboratories. Appl Radiat Isot 2016; 108:92-99. [DOI: 10.1016/j.apradiso.2015.12.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 12/08/2015] [Indexed: 10/22/2022]
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21
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Weißhuhn J, Mark T, Martin M, Müller P, Seifert A, Spange S. Ternary organic–inorganic nanostructured hybrid materials by simultaneous twin polymerization. Polym Chem 2016. [DOI: 10.1039/c6py00903d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The acid and base catalyzed simultaneous twin polymerization to produce ternary organic–inorganic nanostructured hybrid materials consisting of a cross-linked phenolic resin, silica and a disubstituted polysiloxane.
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Affiliation(s)
- J. Weißhuhn
- Department of Polymer Chemistry
- Institute of Chemistry
- Technische Universität Chemnitz
- D-09111 Chemnitz
- Germany
| | - T. Mark
- BASF SE
- D-67056 Ludwigshafen
- Germany
| | - M. Martin
- Department of Polymer Chemistry
- Institute of Chemistry
- Technische Universität Chemnitz
- D-09111 Chemnitz
- Germany
| | | | - A. Seifert
- Department of Polymer Chemistry
- Institute of Chemistry
- Technische Universität Chemnitz
- D-09111 Chemnitz
- Germany
| | - S. Spange
- Department of Polymer Chemistry
- Institute of Chemistry
- Technische Universität Chemnitz
- D-09111 Chemnitz
- Germany
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22
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Ebert T, Wollbrink A, Seifert A, John R, Spange S. Multiple polymerization – formation of hybrid materials consisting of two or more polymers from one monomer. Polym Chem 2016. [DOI: 10.1039/c6py01619g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The synthesis of hybrid materials consisting of three different components from only one monomer is reported for the first time.
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Affiliation(s)
- T. Ebert
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | - A. Wollbrink
- Institute of Physical Chemistry and Electrochemistry
- Leibniz University Hannover
- D-30167 Hannover
- Germany
| | - A. Seifert
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | - R. John
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
| | - S. Spange
- Polymer Chemistry
- Technische Universität Chemnitz
- 09107 Chemnitz
- Germany
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Abstract
We describe a novel approach for fabricating customized convex as well as concave micro-lenses using substrates with sophisticated pinning architecture and utilizing a drop-on-demand jet printer. The polymeric lens material deposited on the wafer is cured by UV light irradiation yielding lenses with high quality surfaces. Surface shape and roughness of the cured polymer lenses are characterized by white light interferometry. Their optical quality is demonstrated by imaging an USAF1951 test chart. The evaluated modulation transfer function is compared to Zemax simulations as a benchmark for the fabricated lenses.
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25
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Ruhhammer J, Zens M, Goldschmidtboeing F, Seifert A, Woias P. Highly elastic conductive polymeric MEMS. Sci Technol Adv Mater 2015; 16:015003. [PMID: 27877753 PMCID: PMC5036488 DOI: 10.1088/1468-6996/16/1/015003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 12/18/2014] [Indexed: 05/18/2023]
Abstract
Polymeric structures with integrated, functional microelectrical mechanical systems (MEMS) elements are increasingly important in various applications such as biomedical systems or wearable smart devices. These applications require highly flexible and elastic polymers with good conductivity, which can be embedded into a matrix that undergoes large deformations. Conductive polydimethylsiloxane (PDMS) is a suitable candidate but is still challenging to fabricate. Conductivity is achieved by filling a nonconductive PDMS matrix with conductive particles. In this work, we present an approach that uses new mixing techniques to fabricate conductive PDMS with different fillers such as carbon black, silver particles, and multiwalled carbon nanotubes. Additionally, the electrical properties of all three composites are examined under continuous mechanical stress. Furthermore, we present a novel, low-cost, simple three-step molding process that transfers a micro patterned silicon master into a polystyrene (PS) polytetrafluoroethylene (PTFE) replica with improved release features. This PS/PTFE mold is used for subsequent structuring of conductive PDMS with high accuracy. The non sticking characteristics enable the fabrication of delicate structures using a very soft PDMS, which is usually hard to release from conventional molds. Moreover, the process can also be applied to polyurethanes and various other material combinations.
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Affiliation(s)
- J Ruhhammer
- Laboratory for Design of Microsystems, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
| | - M Zens
- Laboratory for Design of Microsystems, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
| | - F Goldschmidtboeing
- Laboratory for Design of Microsystems, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
| | - A Seifert
- Gisela and Erwin Sick Chair of Micro-optics, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
| | - P Woias
- Laboratory for Design of Microsystems, Department of Microsystems Engineering—IMTEK, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
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Schneider MO, Engel A, Fasching PA, Häberle L, Binder EB, Voigt F, Grimm J, Faschingbauer F, Eichler A, Dammer U, Rebhan D, Amann M, Raabe E, Goecke TW, Quast C, Beckmann MW, Kornhuber J, Seifert A, Burghaus S. Genetische Varianten in Genen des Stresshormon-Signalweges und depressive Symptome während und nach der Schwangerschaft. Geburtshilfe Frauenheilkd 2014. [DOI: 10.1055/s-0034-1388587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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27
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Göring M, Seifert A, Schreiter K, Müller P, Spange S. A non-aqueous procedure to synthesize amino group bearing nanostructured organic-inorganic hybrid materials. Chem Commun (Camb) 2014; 50:9753-6. [PMID: 25023389 DOI: 10.1039/c4cc03640a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Amino-functionalized organic-inorganic hybrid materials with a narrow distributed nanostructure of 2-4 nm in size were obtained by means of a template-free and non-aqueous procedure. Simultaneous twin polymerization of novel amino group containing twin monomers with 2,2'-spirobi[4H-1,3,2-benzodioxasiline] has been applied for this purpose. The amino groups of the organic-inorganic hybrid material are useful for post derivatization.
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Affiliation(s)
- M Göring
- Department of Polymer Chemistry, Institute of Chemistry, Technische Universität Chemnitz, Strasse der Nationen 62, D-09111 Chemnitz, Germany.
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28
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Thiele S, Seifert A, Herkommer AM. Wave-optical design of a combined refractive-diffractive varifocal lens. Opt Express 2014; 22:13343-13350. [PMID: 24921528 DOI: 10.1364/oe.22.013343] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A novel type of integrated refractive-diffractive varifocal membrane lens is designed and analyzed by wave-optical methods. In contrast to other hybrid devices, the diffractive microstructure is directly imprinted onto the soft deflecting membrane, allowing for a high level of integration. Elastic deformation is taken into account by mechanical simulations with the finite element method (FEM). We show, that the superimposed structure can considerably suppress chromatic and spherical aberration. Furthermore, our algorithm is successfully applied to design a confocal hyperspectral lens.
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29
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Keillor ME, Erikson LE, Aalseth CE, Day AR, Fuller ES, Glasgow BD, Hoppe EW, Hossbach TW, Mizouni LK, Myers AW, Overman CT, Seifert A, Stavenger TJ. Empirical correction of crosstalk in a low-background germanium γ–γ analysis system. J Radioanal Nucl Chem 2013. [DOI: 10.1007/s10967-012-2143-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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30
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Foerster K, Theodor M, Fiala J, Ruh D, Ruhhammer J, Seifert A, Heilmann C, Zappe H, Beyersdorf F. A novel implantable subcutaneous sensor for long term blood pressure and blood oxygen saturation measurement – first in vivo results. Thorac Cardiovasc Surg 2013. [DOI: 10.1055/s-0032-1332498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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31
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Bode S, Bose RK, Matthes S, Ehrhardt M, Seifert A, Schacher FH, Paulus RM, Stumpf S, Sandmann B, Vitz J, Winter A, Hoeppener S, Garcia SJ, Spange S, van der Zwaag S, Hager MD, Schubert US. Self-healing metallopolymers based on cadmium bis(terpyridine) complex containing polymer networks. Polym Chem 2013. [DOI: 10.1039/c3py00288h] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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32
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Mace EK, Aalseth CE, Bonicalzi RM, Day AR, Hoppe EW, Keillor ME, Myers AW, Overman CT, Seifert A. Controlling low-rate signal path microdischarge for an ultra-low-background proportional counter. J Radioanal Nucl Chem 2012. [DOI: 10.1007/s10967-012-2042-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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33
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Seifert A, Ledermann N, Hiboux S, Muralt P. Study of the Transverse Piezoelectric Coefficient of Pb(Zr,Ti)O3 Thin Films as a Function of Texture and Composition. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-596-535] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractThe effective transverse piezoelectric coefficient was measured on 1 μm thick sol-gel processed Pb(Zr,Ti)O3 (PZT) thin films as a function of texture and composition. Optimal values were obtained with PZT films of {100} texture near the morphotropic phase boundary (53/47). The best value amounted to -12 C/m2
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Förster K, Bingger P, Fiala J, Gehrke R, Theodor M, Seifert A, Heilmann C, Woias P, Zappe H, Beyersdorf F. A new implantable pulse oximetry sensor – first long-term implantation in a domestic pig. Thorac Cardiovasc Surg 2010. [DOI: 10.1055/s-0029-1246674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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35
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Schröder H, Wu DF, Seifert A, Rankovic M, Schulz S, Höllt V, Koch T. Allosteric modulation of metabotropic glutamate receptor 5 affects phosphorylation, internalization, and desensitization of the micro-opioid receptor. Neuropharmacology 2009; 56:768-78. [PMID: 19162047 DOI: 10.1016/j.neuropharm.2008.12.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 12/12/2008] [Accepted: 12/20/2008] [Indexed: 11/16/2022]
Abstract
Recent evidence suggests that opioid analgesia and tolerance can be modulated by metabotropic glutamate receptors. Therefore, we studied the functional coupling and desensitization of the micro-opioid receptor (MOR) in human embryonic kidney (HEK) 293 cells which co-express metabotropic glutamate receptor 5 (mGluR5). As demonstrated by the D-Ala2,N-MePhe4,Gl-ol5-enkephalin (DAMGO)-induced inhibition of intracellular cAMP level and by binding studies, the co-expression of mGluR5 had no substantial effect on the agonist binding sites and functional coupling of the MOR. However, in MOR/ mGluR5 co-expressing cells, the non-competitive mGluR5 antagonist MPEP (2-methyl-6-(phenyl-ethynyl)-pyridine) decreases the DAMGO-induced MOR phosphorylation, internalization, and desensitization, whereas non-selective competitive mGluR antagonists or agonists had no effects. These findings indicate that an allosteric modulation of mGluR5 can affect the agonist-induced MOR signalling and regulation. As a mechanistic basis for the observed effects we suggested an interaction/heterodimerization of MOR and mGluR5, which is supported by the DAMGO-induced co-internalization of MOR and mGluR5 and by the increase of MPEP binding sites (Bmax) and a change of the binding affinity (K(D)) of mGluR5 receptors after the co-expression of MOR. In addition, co-immunoprecipitation experiments revealed evidence for an interaction between MOR and mGluR5 which is facilitated by MPEP treatment.
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Affiliation(s)
- H Schröder
- Dept of Pharmacology and Toxicology, Otto-von-Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany.
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36
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Hartung G, Queißer W, Diezler P, Hagmüller E, Edler L, Jacob I, Wojatschek C, Seifert A, Weiss H, Weh HJ, Hoffknecht M, Clemens M, Fritze D, Katz R, Härle M. Adjuvant Chemotherapy with 5-Fluorouracil and Folinic Acid in Colorectal Cancer: Evaluation of Toxicity. Oncol Res Treat 2009. [DOI: 10.1159/000218760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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37
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Knippertz P, Trentmann J, Seifert A. High‐resolution simulations of convective cold pools over the northwestern Sahara. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd011271] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Abstract
OBJECTIVE The prognosis of large-vessel GCA (LV-GCA) has not yet been investigated. How does it compare to GCA without arm vasculitis (GCA controls)? METHODS Charts of 53 LV-GCA patients and 53 GCA controls were reviewed following a predetermined protocol. Telephone interviews of patients or their primary care physicians were conducted. Forty LV-GCA patients underwent follow-up duplex ultrasound examinations of proximal arm arteries. RESULTS The mean observation time was 50 (s.d. +/- 31) months. None of the LV-GCA patients developed ischaemic arm complications. In 30%, proximal arm artery wall swelling disappeared completely. It decreased in 53%. In 8% it remained unchanged, in 5% it increased and in 5% arteries occluded with collateral flow. After the start of treatment, anterior ischaemic optic neuropathy developed neither in LV-GCA patients nor in GCA controls, amaurosis fugax occurred in 4 and 6%, arterial hypertension in 53 and 66%, strokes in 9 and 9%, myocardial infarction in 2 and 2%, diabetes mellitus in 30 and 25%, osteoporosis in 38 and 23%, and osteoporotic fractures in 15 and 4%, respectively. Mean corticosteroid dose was 3.7 mg/day. Mean duration of therapy was 42 months. All differences were insignificant. Four LV-GCA patients developed vasculitic popliteal artery stenoses. CONCLUSIONS The prognosis of LV-GCA is benign with regard to ischaemic complications. Proximal artery wall swelling decreases in most cases. Its course is similar to GCA without proximal arm arteritis.
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Affiliation(s)
- W A Schmidt
- Medical Centre for Rheumatology Berlin-Buch, Karower Str. 11, 13125 Berlin, Germany.
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Schmidt WA, Seifert A, Gromnica-Ihle E, Krause A, Natusch A. Ultrasound of proximal upper extremity arteries to increase the diagnostic yield in large-vessel giant cell arteritis. Rheumatology (Oxford) 2008; 47:96-101. [DOI: 10.1093/rheumatology/kem322] [Citation(s) in RCA: 226] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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40
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Nahum A, Seifert A. Technique for backward particle tracking in a flow field. Phys Rev E Stat Nonlin Soft Matter Phys 2006; 74:016701. [PMID: 16907210 DOI: 10.1103/physreve.74.016701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Revised: 02/03/2006] [Indexed: 05/11/2023]
Abstract
A numerical method to determine the history of particle paths is presented and its application for mixing quantification is illustrated. When more than one source exists in a flow field, the current technique can reveal the particle's identity found in any time and place in the field, by backward tracking its origin. Since the particle position at a preceding time is not known, the velocity vector is implicit. To resolve this uncertainty, a three-stage iterative procedure is developed and implemented. The current particle velocity is multiplied by the time increment and the product is used to estimate the previous time increment particle position. Two velocity matrices are generated on a mesh around the estimated position. The first matrix is the Eulerian velocity field interpolated on the mesh. The second matrix contains velocity vectors that point to the current particle position. A correlation matrix is calculated from the two velocity matrices in order to resolve the actual particle position in the previous time increment. Determination of the time increments' size is performed by checking the maximum of the correlation matrix. The new algorithm was validated using a numerical solution of the confined twin-jet flow at low Reynolds number. This flow performs a Hopf bifurcation at a Reynolds number of about 30, therefore chaotic trajectories might exist in the flow. First, the convergence of the backward particle path to the streamlines in steady flow was demonstrated. Convergence of the particle paths for various time increments was achieved also at the unsteady two-dimensional confined twin-jet flow. When the flow has more than one source, the proposed tracking method can be applied to generate complete and ordered particle source images in any desired position and time in the flow field. Maps of particle sources are used to visualize the flow patterns and the stretched interface between the two fluid sources. Those maps are demonstrated as a powerful tool for mixing quantification and can be implemented also for pollution source detection and many other fluid dynamics applications.
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Affiliation(s)
- A Nahum
- School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, P.O. Box 39040, Tel Aviv 69978, Israel
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Mühlstädt M, Stransky N, Seifert A, Kleinpeter E, Meinhold H. Zur Molekülverknüpfung mit Schwefelchloriden. V. Die Reaktion von Dichlorsulfan mit Allyl-phenyl-äthern. Eine Synthese für 3-Chlormethyl-2,3-dihydro-1,4-benzoxathiine durch intramolekulare Sulfenylierung. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/prac.19783200114] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Sauer J, Weyer T, Seifert A. [Mitigated erysipelas after implantation of foreign material]. Zentralbl Chir 2004; 129:220-4. [PMID: 15237331 DOI: 10.1055/s-2004-822741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
When an infection occurs in the incisional area following surgery where foreign materials (i. e. endoprostheses, metal plates or plastic meshes) are implanted, a revision may become necessary because an infection in the area of the implant and involvement of the implant itself cannot be ruled out. In the case of a mitigated erysipelas, cultures taken during the revision seldom show bacterial growth. The disease progresses because surgery does not solve the problem of a weakened immune system and lymph stasis; on the contrary, it usually deteriorates the situation. A high dose antibiotic regimen is recommended as therapy for the mitigated erysipelas instead of an operative revision orally given. levofloxacin has proven to be successful reducing the recurrence rate. The course of two patients with mitigated erysipelas is represented for example in form of case studies. The patients were underwent several surgical revisions. But we had not to explant the endoprostheses at all. Finally both patients were treated with levofloxacin without further relapses.
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Affiliation(s)
- J Sauer
- Loreley-Kliniken, Chirurgische Abteilung, Schwerin.
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Kehlen A, Seifert A, Klonisch T, Hombach-Klonisch S, Langner J, Hoang-Vu C. Autotaxin is linked with differential gene expression of IL-8, ICAM/CD54 and the tumor-associated antigen GAGE in thyroid carcinomas. Exp Clin Endocrinol Diabetes 2004. [DOI: 10.1055/s-2004-819242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Schiller H, Bartscht T, Arlt A, Zahn MO, Seifert A, Bruhn T, Bruhn HD, Gieseler F. Thrombin as a survival factor for cancer cells: thrombin activation in malignant effusions in vivo and inhibition of idarubicin-induced cell death in vitro. Int J Clin Pharmacol Ther 2002; 40:329-35. [PMID: 12467301 DOI: 10.5414/cpp40329] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES The aim of the experiments shown here, is to demonstrate exemplarily that thrombin can be a survival factor for malignant cells. METHODS Activation of the coagulation system has been examined in patients with acute myeloid leukemia (AML) and non-Hodgkin lymphoma (NHL) before and after chemotherapy as well as in malignant effusions of heavily pretreated patients with solid tumors. Thrombin receptor expression (PAR-I) has been examined on HL-60 cells; the effect ofthrombin on the proliferation of the cells and inhibition of apoptosis induction by idarubicin has been shown. RESULTS Using fibrinopeptide A as an indirect parameter for thrombin activation, we found elevated levels in patients with AML and NHL before and a significant 2-fold increase after chemotherapy (p < 0.02 for the AML group; p < 0.0006 for the NHL group). Apparently, this does not only affect patients with hematological diseases, but also with solid tumors. In order to find out if the tumor cells directly activate thrombin, we examined malignant effusions of patients with different solid tumors. Comparing prothrombin fragment 1 + 2 in ascites and pleural effusions with the patients' serum levels, we found it significantly increased in all cases (mean of 1.96 +/- 0.5 nmol/l in the serum vs. 12.1 +/- 3.6 nmol/l in effusions; p < 0.001). The majority of patients presented elevated serum levels. Additionally, we incubated HL-60 cells (human promyelocytic leukemia) with thrombin prior to treatment with idarubicin. Expression of thrombin receptor (PAR-1) could be verified by FACS-analysis using a monoclonal antibody. HL-60 cells responded with increased proliferation to thrombin exposure with concentrations between 0.3 and 3 U/ml. This effect could be abolished by the addition of hirudin, demonstrating thrombin specificity. In these concentrations, thrombin was able to abrogate the induction of apoptosis by idarubicin completely (p < 0.005). CONCLUSIONS Here we give evidence for the role of thrombin as a resistance factor for tumor cells towards chemotherapy. In the light of the fact that thrombin is regularly activated in cancer patients, these findings indicate that thrombin is a clinically relevant cellular resistance factor. A number of pre-clinical and clinical studies imply that inhibition of the coagulation system, e.g. by low-molecular weight heparins or warfarin, increases the effect of chemotherapy.
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Affiliation(s)
- H Schiller
- Department of Internal Medicine, University of Kiel, Germany
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Bayer A, Kopitzke J, Noll F, Seifert A, Wendorff JH. Polymer Dispersed Discotics: Structure, Dynamics, and Optoelectronic Properties. Macromolecules 2001. [DOI: 10.1021/ma001470g] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. Bayer
- Department of Chemistry and Materials Science Center, Philipps University, Marburg, Germany
| | - J. Kopitzke
- Department of Chemistry and Materials Science Center, Philipps University, Marburg, Germany
| | - F. Noll
- Department of Chemistry and Materials Science Center, Philipps University, Marburg, Germany
| | - A. Seifert
- Department of Chemistry and Materials Science Center, Philipps University, Marburg, Germany
| | - J. H. Wendorff
- Department of Chemistry and Materials Science Center, Philipps University, Marburg, Germany
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Klein U, Karzai W, Bloos F, Wohlfarth M, Gottschall R, Fritz H, Gugel M, Seifert A. Role of fiberoptic bronchoscopy in conjunction with the use of double-lumen tubes for thoracic anesthesia: a prospective study. Anesthesiology 1998; 88:346-50. [PMID: 9477054 DOI: 10.1097/00000542-199802000-00012] [Citation(s) in RCA: 178] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Fiberoptic bronchoscopy has been recommended to verify the position of double-lumen tubes (DLT), but this remains controversial. The authors studied the role of bronchoscopy for placing and monitoring right- and left-sided DLTs after blind intubation and after positioning the patient. METHODS Two hundred patients having thoracic surgery requiring DLT insertion were prospectively studied. "Blind" tracheal intubations were done with 163 left-sided and 37 right-sided disposable polyvinyl chloride Robertshaw tubes. Bronchoscopy was performed by a different anesthesiologist after intubation and conventional clinical verification of correct placement and after patient positioning for thoracotomy. A DLT was considered malpositioned when it had to be moved >0.5 cm to correct its position. Critical malpositions were those that might have affected patient safety or influenced the surgical procedure if left uncorrected. RESULTS After "blind" DLT intubation, clinical evidence of malpositioning was found in 28 patients. This was confirmed by fiberoptic assessment. In 172 patients in whom placement was judged correct by clinical assessment, malpositioning was detected by bronchoscopy in 79 cases, 25 of which were critical. After patient positioning, DLTs were found to be displaced in 93 patients, 48 of which were critical. Right-sided DLTs were significantly more likely to be malpositioned than were left-sided DLTs. Two complications were related to unsatisfactory lung separation in the 200 patients studied. CONCLUSIONS After blind intubation and patient positioning, more than one third of DLTs required repositioning. Routine bronchoscopy is therefore recommended after intubation and after patient positioning.
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Affiliation(s)
- U Klein
- Department of Anesthesiology and Intensive Care Medicine, University Hospital, Friedrich-Schiller-University Jena, Germany.
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Hartung G, Queißer W, Maas K, Diezler P, Hagmüller E, Edler L, Kopp-Schneider A, Weniger J, Baur A, Pabst T, Jacob I, Wojatschek C, Seifert A, Weh HJ, Janssen N, Engel M, Drost H, Stockert H, Lehnigk S. Adjuvant Radio-Chemotherapy with 5-Fluorouracil and Folinic Acid in Stage II and III Rectal Cancer: Interim Analysis. Oncol Res Treat 1997. [DOI: 10.1159/000218944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Schwenke KD, Staatz A, Mothes R, Seifert A, Dautzenberg H. Physico-chemical characterization of legumin-T from faba bean (Vicia faba L). Int J Pept Protein Res 1996; 47:254-9. [PMID: 8738650 DOI: 10.1111/j.1399-3011.1996.tb01353.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Legumin-T, the high-molecular mass product of limited tryptic hydrolysis of faba bean legumin, was investigated using hydrodynamic methods, static light scattering, fluorescence and ultraviolet spectroscopy. The following physico-chemical parameters were determined in a high-ionic strength buffer system: molecular mass, 2.4 x 10(5) g/mol; sedimentation coefficient, SO20 = 10.8 x 10(-13)Si; diffusion coefficient, DO20 = 4.1 x 10(-7) cm2 s-1; intrinsic viscosity, [eta] = 3.51 mL/g; partial specific volume, v = 0.719 mL/g; frictional ratio, f/f0 = 1.22; shape factor, beta = 2.17 x 10(6). Conformational changes during the formation of legumin-T can be deduced from the fluorescence emission and UV spectra.
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Affiliation(s)
- K D Schwenke
- WIP-Research Group in Plant Protein Chemistry, University of Potsdam, Germany
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Seifert A, Heinevetter L, Cölfen H, Harding S. Characterization of gliadin-galactomannan incubation mixtures by analytical ultracentrifugation—Part I. Sedimentation velocity. Carbohydr Polym 1995. [DOI: 10.1016/0144-8617(96)00004-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Seifert A. Characterization of gliadin-galactomannan incubation mixtures by analytical ultracentrifugation. Carbohydr Polym 1994. [DOI: 10.1016/0144-8617(94)90241-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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