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Zupanič F, Žist S, Albu M, Letofsky-Papst I, Burja J, Vončina M, Bončina T. Dispersoids in Al-Mg-Si Alloy AA 6086 Modified by Sc and Y. Materials (Basel) 2023; 16:2949. [PMID: 37109786 PMCID: PMC10142497 DOI: 10.3390/ma16082949] [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] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/22/2023] [Accepted: 04/05/2023] [Indexed: 06/19/2023]
Abstract
The aluminium alloy AA 6086 attains the highest room temperature strength among Al-Mg-Si alloys. This work studies the effect of Sc and Y on the formation of dispersoids in this alloy, especially L12-type ones, which can increase its high-temperature strength. A comprehensive investigation was carried out using light microscopy (LM), scanning (SEM), and transmission (TEM) electron microscopy, energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and dilatometry to obtain the information regarding the mechanisms and kinetics of dispersoid formation, particularly during isothermal treatments. Sc and Y caused the formation of L12 dispersoids during heating to homogenization temperature and homogenization of the alloys, and during isothermal heat treatments of the as-cast alloys (T5 temper). The highest hardness of Sc and (Sc + Y) modified alloys was attained by heat-treating alloys in the as-cast state in the temperature range between 350 °C and 450 °C (via T5 temper).
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Affiliation(s)
- Franc Zupanič
- Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia
| | - Sandi Žist
- Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia
- Impol 2000 d.d., Partizanska ulica 38, SI-2310 Slovenska Bistrica, Slovenia
| | - Mihaela Albu
- Graz Centre for Electron Microscopy, Steyrergasse 17, A-8010 Graz, Austria
| | - Ilse Letofsky-Papst
- Institute of Electron Microscopy and Nanoanalysis and Centre for Electron Microscopy, Graz University of Technology, NAWI Graz, Steyrergasse 17, A-8010 Graz, Austria
| | - Jaka Burja
- Institute of Metals & Technology, Lepi pot 11, SI-1000 Ljubljana, Slovenia
| | - Maja Vončina
- Faculty of Natural Sciences and Engineering, University of Ljubljana, Aškerčeva cesta 12, SI-1000 Ljubljana, Slovenia
| | - Tonica Bončina
- Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia
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2
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Martín Vilardell A, Cantillo Alzamora V, Bauso LV, Madrid C, Krakhmalev P, Albu M, Yadroitsava I, Yadroitsev I, Garcia-Giralt N. Effect of Heat Treatment on Osteoblast Performance and Bactericidal Behavior of Ti6Al4V(ELI)-3at.%Cu Fabricated by Laser Powder Bed Fusion. J Funct Biomater 2023; 14:jfb14020063. [PMID: 36826862 PMCID: PMC9962850 DOI: 10.3390/jfb14020063] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/10/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
Cu addition to alloys for biomedical applications has been of great interest to reduce bacterial growth. In situ-alloyed Ti6Al4V(ELI)-3at.%Cu was successfully manufactured by laser powder bed fusion (L-PBF). Even so, post-heat treatments are required to avoid distortions and/or achieve required/desired mechanical and fatigue properties. The present study is focused on the investigation of microstructural changes in L-PBF Ti6Al4V(ELI)-3at.%Cu after stress relieving and annealing treatments, as well as their influence on osteoblast and bactericidal behavior. After the stress relieving treatment, a homogenously distributed β phase and CuTi2 intermetallic precipitates were observed over the α' matrix. The annealing treatment led to the increase in amount and size of both types of precipitates, but also to phase redistribution along α lamellas. Although microstructural changes were not statistically significant, such increase in β and CuTi2 content resulted in an increase in osteoblast proliferation after 14 days of cell culture. A significant bactericidal behavior of L-PBF Ti6Al4V(ELI)-3at.%Cu by means of ion release was found after the annealing treatment, provably due to the easier release of Cu ions from β phase. Biofilm formation was inhibited in all on Cu-alloyed specimens with stress relieving but also annealing treatment.
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Affiliation(s)
- Anna Martín Vilardell
- Department of Engineering and Physics, Karlstad University, 651 88 Karlstad, Sweden
- Correspondence: (A.M.V.); (P.K.)
| | - Vanesa Cantillo Alzamora
- IMIM (Institut Hospital del Mar d’Investigacions Mèdiques), CIBERFES, ISCIII, Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Luana Vittoria Bauso
- IMIM (Institut Hospital del Mar d’Investigacions Mèdiques), CIBERFES, ISCIII, Doctor Aiguader 88, 08003 Barcelona, Spain
- Department of Clinical and Experimental Medicine, University of Messina, Consolare Valeria 1, 98125 Messina, Italy
| | - Cristina Madrid
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain
| | - Pavel Krakhmalev
- Department of Engineering and Physics, Karlstad University, 651 88 Karlstad, Sweden
- Correspondence: (A.M.V.); (P.K.)
| | - Mihaela Albu
- Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz, Austria
| | - Ina Yadroitsava
- Department of Mechanical Engineering and Mechatronics, Central University of Technology, Bloemfontein 9300, South Africa
| | - Igor Yadroitsev
- Department of Mechanical Engineering and Mechatronics, Central University of Technology, Bloemfontein 9300, South Africa
| | - Natalia Garcia-Giralt
- IMIM (Institut Hospital del Mar d’Investigacions Mèdiques), CIBERFES, ISCIII, Doctor Aiguader 88, 08003 Barcelona, Spain
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Kölbl D, Memic A, Schnideritsch H, Wohlmuth D, Klösch G, Albu M, Giester G, Bujdoš M, Milojevic T. Thermoacidophilic Bioleaching of Industrial Metallic Steel Waste Product. Front Microbiol 2022; 13:864411. [PMID: 35495675 PMCID: PMC9043896 DOI: 10.3389/fmicb.2022.864411] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/14/2022] [Indexed: 11/13/2022] Open
Abstract
The continuous deposition of hazardous metalliferous wastes derived from industrial steelmaking processes will lead to space shortages while valuable raw metals are being depleted. Currently, these landfilled waste products pose a rich resource for microbial thermoacidophilic bioleaching processes. Six thermoacidophilic archaea (Sulfolobus metallicus, Sulfolobus acidocaldarius, Metallosphaera hakonensis, Metallosphaera sedula, Acidianus brierleyi, and Acidianus manzaensis) were cultivated on metal waste product derived from a steelmaking process to assess microbial proliferation and bioleaching potential. While all six strains were capable of growth and bioleaching of different elements, A. manzaensis outperformed other strains and its bioleaching potential was further studied in detail. The ability of A. manzaensis cells to break down and solubilize the mineral matrix of the metal waste product was observed via scanning and transmission electron microscopy. Refinement of bioleaching operation parameters shows that changes in pH influence the solubilization of certain elements, which might be considered for element-specific solubilization processes. Slight temperature shifts did not influence the release of metals from the metal waste product, but an increase in dust load in the bioreactors leads to increased element solubilization. The formation of gypsum crystals in course of A. manzaensis cultivation on dust was observed and clarified using single-crystal X-ray diffraction analysis. The results obtained from this study highlight the importance of thermoacidophilic archaea for future small-scale as well as large-scale bioleaching operations and metal recycling processes in regard to circular economies and waste management. A thorough understanding of the bioleaching performance of thermoacidophilic archaea facilitates further environmental biotechnological advancements.
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Affiliation(s)
- Denise Kölbl
- Extremophiles/Space Biochemistry Group, Department of Biophysical Chemistry, University of Vienna, Vienna, Austria
| | - Alma Memic
- Extremophiles/Space Biochemistry Group, Department of Biophysical Chemistry, University of Vienna, Vienna, Austria
| | | | | | | | - Mihaela Albu
- Graz Centre for Electron Microscopy, Graz, Austria
| | - Gerald Giester
- Department of Mineralogy and Crystallography, University of Vienna, Vienna, Austria
| | - Marek Bujdoš
- Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Tetyana Milojevic
- Extremophiles/Space Biochemistry Group, Department of Biophysical Chemistry, University of Vienna, Vienna, Austria
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Gößler M, Hengge E, Bogar M, Albu M, Knez D, Amenitsch H, Würschum R. In Situ Study of Nanoporosity Evolution during Dealloying AgAu and CoPd by Grazing-Incidence Small-Angle X-ray Scattering. J Phys Chem C Nanomater Interfaces 2022; 126:4037-4047. [PMID: 35273676 PMCID: PMC8900123 DOI: 10.1021/acs.jpcc.1c09592] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/21/2022] [Indexed: 06/14/2023]
Abstract
Electrochemical dealloying has become a standard technique to produce nanoporous network structures of various noble metals, exploiting the selective dissolution of one component from an alloy. While achieving nanoporosity during dealloying has been intensively studied for the prime example of nanoporous Au from a AgAu alloy, dealloying from other noble-metal alloys has been rarely investigated in the scientific literature. Here, we study the evolution of nanoporosity in the electrochemical dealloying process for both CoPd and AgAu alloys using a combination of in situ grazing-incidence small-angle X-ray scattering (GISAXS), kinetic Monte Carlo (KMC) simulations, and scanning transmission electron microscopy (STEM). When comparing dealloying kinetics, we find a more rapid progression of the dealloying front for CoPd and also a considerably slower coarsening of the nanoporous structure for Pd in relation to Au. We argue that our findings are natural consequences of the effectively higher dealloying potential and the higher interatomic binding energy for the CoPd alloy. Our results corroborate the understanding of electrochemical dealloying on the basis of two rate equations for dissolution and surface diffusion and suggest the general applicability of this dealloying mechanism to binary alloys. The present study contributes to the future tailoring of structural size in nanoporous metals for improved chemical surface activity.
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Affiliation(s)
- Markus Gößler
- Institute
of Materials Physics, Graz University of
Technology, Petersgasse 16, 8010 Graz, Austria
| | - Elisabeth Hengge
- Institute
of Materials Physics, Graz University of
Technology, Petersgasse 16, 8010 Graz, Austria
| | - Marco Bogar
- CERIC-ERIC
C/o Elettra Sincrotrone, S.S. 14 Km 163.5, 34149 Trieste, Italy
- Institute
for Inorganic Chemistry, Graz University
of Technology, Stremayrgasse
9, 8010 Graz, Austria
| | - Mihaela Albu
- Graz
Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz, Austria
| | - Daniel Knez
- Institute
of Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
| | - Heinz Amenitsch
- Institute
for Inorganic Chemistry, Graz University
of Technology, Stremayrgasse
9, 8010 Graz, Austria
| | - Roland Würschum
- Institute
of Materials Physics, Graz University of
Technology, Petersgasse 16, 8010 Graz, Austria
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5
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Albu M, Panzirsch B, Schröttner H, Mitsche S, Reichmann K, Poletti MC, Kothleitner G. High-Resolution Microstructure Characterization of Additively Manufactured X5CrNiCuNb17-4 Maraging Steel during Ex and In Situ Thermal Treatment. Materials (Basel) 2021; 14:ma14247784. [PMID: 34947383 PMCID: PMC8707314 DOI: 10.3390/ma14247784] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 11/16/2022]
Abstract
Powder and selective laser melting (SLM) additively manufactured parts of X5CrNiCuNb17-4 maraging steel were systematically investigated by electron microscopy to understand the relationship between the properties of the powder grains and the microstructure of the printed parts. We prove that satellites, irregularities and superficial oxidation of powder particles can be transformed into an advantage through the formation of nanoscale (AlMnSiTiCr) oxides in the matrix during the printing process. The nano-oxides showed extensive stability in terms of size, spherical morphology, chemical composition and crystallographic disorder upon in situ heating in the scanning transmission electron microscope up to 950 °C. Their presence thus indicates a potential for oxide-dispersive strengthening of this steel, which may be beneficial for creep resistance at elevated temperatures. The nucleation of copper clusters and their evolution into nanoparticles, and the precipitation of Ni and Cr particles upon in situ heating, have been systematically documented as well.
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Affiliation(s)
- Mihaela Albu
- Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz, Austria;
- Correspondence: ; Tel.: +43-316-873-8348
| | - Bernd Panzirsch
- ÖGI- Austrian Foundry Institute, Parkstraße 21, 8700 Leoben, Austria;
| | - Hartmuth Schröttner
- Institute of Electron Microscopy and Nanoanalysis, TU Graz, Steyrergasse 17, 8010 Graz, Austria; (H.S.); (S.M.)
| | - Stefan Mitsche
- Institute of Electron Microscopy and Nanoanalysis, TU Graz, Steyrergasse 17, 8010 Graz, Austria; (H.S.); (S.M.)
| | - Klaus Reichmann
- Institute for Chemistry and Technology of Materials, TU Graz, Stremayrgasse 9, 8010 Graz, Austria;
| | - Maria Cecilia Poletti
- Institute of Materials Science, Joining and Forming, TU Graz, Kopernikusgasse 24, 8010 Graz, Austria;
| | - Gerald Kothleitner
- Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz, Austria;
- Institute of Electron Microscopy and Nanoanalysis, TU Graz, Steyrergasse 17, 8010 Graz, Austria; (H.S.); (S.M.)
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6
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Vilardell AM, Takezawa A, du Plessis A, Takata N, Krakhmalev P, Kobashi M, Albu M, Kothleitner G, Yadroitsava I, Yadroitsev I. Mechanical behavior of in-situ alloyed Ti6Al4V(ELI)-3 at.% Cu lattice structures manufactured by laser powder bed fusion and designed for implant applications. J Mech Behav Biomed Mater 2020; 113:104130. [PMID: 33049622 DOI: 10.1016/j.jmbbm.2020.104130] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 08/18/2020] [Revised: 09/22/2020] [Accepted: 10/01/2020] [Indexed: 10/23/2022]
Abstract
In the present study, cellular lattice structures for implant applications are reported for the first-time incorporating copper directly by in-situ alloying in the laser powder bed fusion process. The aim to incorporate 3 at.% Cu into Ti6Al4V(ELI) is selected for improved antibacterial properties while maintaining appropriate mechanical properties. Previously, topologically optimized Ti6Al4V(ELI) lattice structures were successfully designed, manufactured and studied for implant applications. The development of a new alloy produced by in-situ alloying of elemental powder mixture of Ti6Al4V(ELI) and pure Cu powders was used here for the production of identical lattice structures with improved antibacterial properties. One of the same as-designed CAD models was used for the manufacturing of these lattices compared to previous work on pure Ti6Al4V(ELI) lattices, making direct comparison of mechanical properties possible. Similar manufacturability highlights the applicability of this alloying technique to other lattice designs. Microstructural characterization was performed by optical and electron microscopies, as well as microCT. Mechanical characterization was performed by means of compression tests and hardness measurements. Results showed that in-situ alloying with copper leads to the formation of localized Cu-rich regions, refinement of martensitic phase and the formation of CuTi2 intermetallic precipitates, which increased the hardness and strength of the material. Deviations in wall thickness between the as-designed and as-manufactured lattices led to anisotropy of the mechanical properties of the lattices. Higher compressive strength values were obtained when thicker walls were oriented along the loading direction. Nevertheless, alloying with Cu had a higher impact on the compressive strength of lattice structure than the wall thickness deviations. The direct in-situ alloying of copper in Ti6Al4V(ELI) is a promising route for direct manufacturing of antibacterial implants.
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Affiliation(s)
- A M Vilardell
- Karlstad University, Department of Engineering and Physics, Karlstad, SE-651 88, Sweden.
| | - A Takezawa
- Dept. of Applied Mechanics and Aerospace Engineering, School of Fundamental Science and Engineering, Waseda University, 59-311, 3-4-1 Okubo, Shinjuku-ku, Tokyo, 169-8555, Japan
| | - A du Plessis
- Research Group 3D Innovation, Stellenbosch University, Stellenbosch, 7602, South Africa
| | - N Takata
- Dept. of Materials Process Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - P Krakhmalev
- Karlstad University, Department of Engineering and Physics, Karlstad, SE-651 88, Sweden
| | - M Kobashi
- Dept. of Materials Process Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - M Albu
- Graz Centre for Electron Microscopy (ZFE), Steyrergasse 17-3, A-8010, Graz, Austria
| | - G Kothleitner
- Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17-3, A-8010, Graz, Austria
| | - I Yadroitsava
- Dept. of Mechanical and Mechatronics Engineering, Central University of Technology, Bloemfontein, 9300, South Africa
| | - I Yadroitsev
- Dept. of Mechanical and Mechatronics Engineering, Central University of Technology, Bloemfontein, 9300, South Africa
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Rienks EDL, Wimmer S, Sánchez-Barriga J, Caha O, Mandal PS, Růžička J, Ney A, Steiner H, Volobuev VV, Groiss H, Albu M, Kothleitner G, Michalička J, Khan SA, Minár J, Ebert H, Bauer G, Freyse F, Varykhalov A, Rader O, Springholz G. Large magnetic gap at the Dirac point in Bi2Te3/MnBi2Te4 heterostructures. Nature 2019; 576:423-428. [DOI: 10.1038/s41586-019-1826-7] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 10/18/2019] [Indexed: 11/09/2022]
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8
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Gößler M, Albu M, Klinser G, Steyskal EM, Krenn H, Würschum R. Magneto-Ionic Switching of Superparamagnetism. Small 2019; 15:e1904523. [PMID: 31573141 DOI: 10.1002/smll.201904523] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/14/2019] [Indexed: 06/10/2023]
Abstract
Electrochemical reactions represent a promising approach to control magnetization via electric fields. Favorable reaction kinetics have made nanoporous materials particularly interesting for magnetic tuning experiments. A fully reversible ON and OFF switching of magnetism in nanoporous Pd(Co) at room temperature is demonstrated, triggered by electrochemical hydrogen sorption. Comprehensive magnetic characterization in combination with high-resolution scanning transmission electron microscopy reveals the presence of Co-rich, nanometer-sized clusters in the nanoporous Pd matrix with distinct superparamagnetic behavior. The strong magneto-ionic effect arises from coupling of the magnetic clusters via a Ruderman-Kittel-Kasuya-Yoshida-type interaction in the Pd matrix which is strengthened upon hydrogen sorption. This approach offers a new pathway for the voltage control of magnetism, for application in spintronic or microelectromagnetic devices.
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Affiliation(s)
- Markus Gößler
- Institute of Materials Physics, Graz University of Technology, Petersgasse 16, A-8010, Graz, Austria
| | - Mihaela Albu
- Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, A-8010, Graz, Austria
| | - Gregor Klinser
- Institute of Materials Physics, Graz University of Technology, Petersgasse 16, A-8010, Graz, Austria
| | - Eva-Maria Steyskal
- Institute of Materials Physics, Graz University of Technology, Petersgasse 16, A-8010, Graz, Austria
| | - Heinz Krenn
- Institute of Physics, University of Graz, Universitätsplatz 5, A-8010, Graz, Austria
| | - Roland Würschum
- Institute of Materials Physics, Graz University of Technology, Petersgasse 16, A-8010, Graz, Austria
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Blazevic A, Albu M, Mitsche S, Rittmann SKMR, Habler G, Milojevic T. Biotransformation of Scheelite CaWO 4 by the Extreme Thermoacidophile Metallosphaera sedula: Tungsten-Microbial Interface. Front Microbiol 2019; 10:1492. [PMID: 31312192 PMCID: PMC6614383 DOI: 10.3389/fmicb.2019.01492] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/14/2019] [Indexed: 01/04/2023] Open
Abstract
The tungsten-microbial interactions and microbial bioprocessing of tungsten ores, which are still underexplored, are the focus of the current study. Here we show that the biotransformation of tungsten mineral scheelite performed by the extreme thermoacidophile Metallosphaera sedula leads to the breakage of scheelite structure and subsequent tungsten solubilization. Total soluble tungsten is significantly higher in cultures containing M. sedula grown on scheelite than the abiotic control, indicating active bioleaching. Advanced analytical electron microscopy was used in order to achieve nanoscale resolution ultrastructural studies of M. sedula grown on tungsten bearing scheelite. In particular, we describe that M. sedula mediated the biotransformation of scheelite, which was accompanied by the release of tungsten into solution and tungsten biomineralization of the cell surface. Furthermore, we observed intracellular incorporation of redox heterogenous Mn- and Fe-containing nano-clusters. Our results highlight unique metallophilic life in hostile environments extending the knowledge of tungsten biogeochemistry. Based on these findings biohydrometallurgical processing of tungsten ores can be further explored. Importantly, biogenic tungsten carbide-like nanolayers described herein are potential targets for developing nanomaterial biotechnology.
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Affiliation(s)
- Amir Blazevic
- Extremophiles/Space Biochemistry Group, Department of Biophysical Chemistry, University of Vienna, Vienna, Austria
| | - Mihaela Albu
- Graz Centre for Electron Microscopy, Graz, Austria
| | | | - Simon K-M R Rittmann
- Archaea Physiology and Biotechnology Group, Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Gerlinde Habler
- Department of Lithospheric Research, University of Vienna, Vienna, Austria
| | - Tetyana Milojevic
- Extremophiles/Space Biochemistry Group, Department of Biophysical Chemistry, University of Vienna, Vienna, Austria
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10
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Milojevic T, Albu M, Blazevic A, Gumerova N, Konrad L, Cyran N. Nanoscale Tungsten-Microbial Interface of the Metal Immobilizing Thermoacidophilic Archaeon Metallosphaera sedula Cultivated With Tungsten Polyoxometalate. Front Microbiol 2019; 10:1267. [PMID: 31275255 PMCID: PMC6593293 DOI: 10.3389/fmicb.2019.01267] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 05/22/2019] [Indexed: 12/15/2022] Open
Abstract
Inorganic systems based upon polyoxometalate (POM) clusters provide an experimental approach to develop artificial life. These artificial symmetric anionic macromolecules with oxidometalate polyhedra as building blocks were shown to be well suited as inorganic frameworks for complex self-assembling and organizing systems with emergent properties. Analogously to mineral cells based on iron sulfides, POMs are considered as inorganic cells in facilitating prelife chemical processes and displaying “life-like” characteristics. However, the relevance of POMs to life-sustaining processes (e.g., microbial respiration) has not yet been addressed, while iron sulfides are very well known as ubiquitous mineral precursors and energy sources for chemolithotrophic metabolism. Metallosphaera sedula is an extreme metallophilic and thermoacidophilic archaeon, which flourishes in hot acid and respires by metal oxidation. In the present study we provide our observations on M. sedula cultivated on tungsten polyoxometalate (W-POM). The decomposition of W-POM macromolecular clusters and the appearance of low molecular weight W species (e.g., WO) in the presence of M. sedula have been detected by electrospray ionization mass spectrometry (ESI-MS) analysis. Here, we document the presence of metalloorganic assemblages at the interface between M. sedula and W-POM resolved down to the nanometer scale using scanning and transmission electron microscopy (SEM and TEM) coupled to electron energy loss spectroscopy (EELS). High-resolution TEM (HR-TEM) and selected-area electron diffraction (SAED) patterns indicated the deposition of redox heterogeneous tungsten species on the S-layer of M. sedula along with the accumulation of intracellular tungsten-bearing nanoparticles, i.e., clusters of tungsten atoms. These results reveal the effectiveness of the analytical spectroscopy coupled to the wet chemistry approach as a tool in the analysis of metal–microbial interactions and microbial cultivation on supramolecular self-assemblages based on inorganic metal clusters. We discuss the possible mechanism of W-POM decomposition by M. sedula in light of unique electrochemical properties of POMs. The findings presented herein highlight unique metallophilicity in hostile environments, extending our knowledge of the relevance of POMs to life-sustaining processes, understanding of the transition of POMs as inorganic prebiotic model to life-sustainable material precursors and revealing biogenic signatures obtained after the decomposition of an artificial inorganic compound, which previously was not associated with any living matter.
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Affiliation(s)
- Tetyana Milojevic
- Extremophiles/Space Biochemistry Group, Department of Biophysical Chemistry, University of Vienna, Vienna, Austria
| | - Mihaela Albu
- Graz Centre for Electron Microscopy, Graz, Austria
| | - Amir Blazevic
- Department of Biophysical Chemistry, University of Vienna, Vienna, Austria
| | - Nadiia Gumerova
- Department of Biophysical Chemistry, University of Vienna, Vienna, Austria
| | - Lukas Konrad
- Graz Centre for Electron Microscopy, Graz, Austria
| | - Norbert Cyran
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna, Austria
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Hagemann N, Joseph S, Schmidt HP, Kammann CI, Harter J, Borch T, Young RB, Varga K, Taherymoosavi S, Elliott KW, McKenna A, Albu M, Mayrhofer C, Obst M, Conte P, Dieguez-Alonso A, Orsetti S, Subdiaga E, Behrens S, Kappler A. Organic coating on biochar explains its nutrient retention and stimulation of soil fertility. Nat Commun 2017; 8:1089. [PMID: 29057875 PMCID: PMC5715018 DOI: 10.1038/s41467-017-01123-0] [Citation(s) in RCA: 175] [Impact Index Per Article: 25.0] [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: 03/16/2017] [Accepted: 08/15/2017] [Indexed: 11/26/2022] Open
Abstract
Amending soil with biochar (pyrolized biomass) is suggested as a globally applicable approach to address climate change and soil degradation by carbon sequestration, reducing soil-borne greenhouse-gas emissions and increasing soil nutrient retention. Biochar was shown to promote plant growth, especially when combined with nutrient-rich organic matter, e.g., co-composted biochar. Plant growth promotion was explained by slow release of nutrients, although a mechanistic understanding of nutrient storage in biochar is missing. Here we identify a complex, nutrient-rich organic coating on co-composted biochar that covers the outer and inner (pore) surfaces of biochar particles using high-resolution spectro(micro)scopy and mass spectrometry. Fast field cycling nuclear magnetic resonance, electrochemical analysis and gas adsorption demonstrated that this coating adds hydrophilicity, redox-active moieties, and additional mesoporosity, which strengthens biochar-water interactions and thus enhances nutrient retention. This implies that the functioning of biochar in soil is determined by the formation of an organic coating, rather than biochar surface oxidation, as previously suggested. Biochar promotes plant growth via a slow release of nutrients; however, a mechanistic understanding of nutrient storage in biochar is lacking. Here, using high-resolution spectromicroscopy and mass spectrometry, the authors identify an organic coating on co-composted particles that enhances nutrient retention.
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Affiliation(s)
- Nikolas Hagemann
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, Tuebingen, 72076, Germany.,Environmental Analytics, Agroscope, Reckenholzstraße 191, 8046, Zurich, Switzerland
| | - Stephen Joseph
- School of Environmental and Life Sciences, Chemistry, University of Newcastle, Callaghan, NSW 2308, Australia.,School of Materials Science and Engineering, University of New South Wales, Kensington, NSW 2052, Australia.,Nanjing Agricultural University, Nanjing, 210095, China
| | - Hans-Peter Schmidt
- Ithaka Institute for Carbon Strategies, Ancienne Eglise 9, Arbaz, 1974, Switzerland
| | - Claudia I Kammann
- Department of Soil Science and Plant Nutrition, WG Climate Change Research for Special Crops, Hochschule Geisenheim University, von-Lade Str. 1, Geisenheim, 65366, Germany
| | - Johannes Harter
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, Tuebingen, 72076, Germany
| | - Thomas Borch
- Department of Soil and Crop Sciences and Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - Robert B Young
- Department of Soil and Crop Sciences and Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - Krisztina Varga
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Sarasadat Taherymoosavi
- School of Environmental and Life Sciences, Chemistry, University of Newcastle, Callaghan, NSW 2308, Australia
| | - K Wade Elliott
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Amy McKenna
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL, 32310-4005, USA
| | - Mihaela Albu
- Austrian Cooperative Research, Centre for Electron Microscopy and Nanoanalysis, Steyrergasse 17, Graz, 8010, Austria
| | - Claudia Mayrhofer
- Austrian Cooperative Research, Centre for Electron Microscopy and Nanoanalysis, Steyrergasse 17, Graz, 8010, Austria
| | - Martin Obst
- BayCEER Analytics, University of Bayreuth, Bayreuth, 95440, Germany
| | - Pellegrino Conte
- Dipartimento di Scienze Agrarie e Forestali, Università degli Studi di Palermo, v.le delle Scienze ed. 4, Palermo, 90128, Italy
| | - Alba Dieguez-Alonso
- Institute of Energy Engineering, Chair for Energy Process Engineering and Conversion Technologies for Renewable Energies, Technische Universität Berlin, Fasanenstraße 89, Berlin, 10623, Germany
| | - Silvia Orsetti
- Environmental Mineralogy and Chemistry, Center for Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, Tuebingen, 72076, Germany
| | - Edisson Subdiaga
- Environmental Mineralogy and Chemistry, Center for Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, Tuebingen, 72076, Germany
| | - Sebastian Behrens
- Department for Civil, Environmental, and Geo-Engineering, University of Minnesota, 500 Pillsbury Drive S.E, Minneapolis, MN, 55455-0116, USA.,BioTechonology Institute, 140 Gortner Labs, 1479 Gortner Avenue, St. Paul, MN, 55108-6106, USA
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, Tuebingen, 72076, Germany.
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Steyskal EM, Qi Z, Pölt P, Albu M, Weissmüller J, Würschum R. Electrochemically Tunable Resistance of Nanoporous Platinum Produced by Dealloying. Langmuir 2016; 32:7757-7764. [PMID: 27406856 DOI: 10.1021/acs.langmuir.6b01734] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The extremely high surface-to-volume ratio of nanoporous platinum (np-Pt) produced by dealloying was applied for tuning electrical resistance by surface charging. In the as-dealloyed state, a characteristic sign-inversion of the charging-induced resistance variation occurs, which can be associated with the electronic structure of PtO. After electrochemical reduction, the relative resistance variations of np-Pt of up to 58% could be generated by electrochemically induced adsorption and desorption, which was 1 order of magnitude larger compared with that of cluster-assembled nanocrystalline Pt. Although the maximum resistance variation was also higher than that of dealloyed nanoporous gold (np-Au), the resistance variation related to the imposed charge was reduced owing to the higher bulk resistance of Pt compared with that of Au. The sign-inversion behavior of the resistance could be recovered by re-oxidation.
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Affiliation(s)
- Eva-Maria Steyskal
- Institute of Materials Physics, Graz University of Technology , Petersgasse 16, A-8010 Graz, Austria
| | - Zhen Qi
- Institute of Materials Physics and Technology, Hamburg-Harburg University of Technology , Eißendorfer Straße 42, D-21073 Hamburg, Germany
| | - Peter Pölt
- Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology , Steyrergasse 17, A-8010 Graz, Austria
| | - Mihaela Albu
- Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology , Steyrergasse 17, A-8010 Graz, Austria
| | - Jörg Weissmüller
- Institute of Materials Physics and Technology, Hamburg-Harburg University of Technology , Eißendorfer Straße 42, D-21073 Hamburg, Germany
- Institute of Materials Research, Helmholtz-Zentrum Geesthacht , Max-Planck-Straße 1, D-21502 Geesthacht, Germany
| | - Roland Würschum
- Institute of Materials Physics, Graz University of Technology , Petersgasse 16, A-8010 Graz, Austria
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Haberfehlner G, Orthacker A, Albu M, Li J, Kothleitner G. Nanoscale voxel spectroscopy by simultaneous EELS and EDS tomography. Nanoscale 2014; 6:14563-9. [PMID: 25349984 DOI: 10.1039/c4nr04553j] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Extending the capabilities of electron tomography with advanced imaging techniques and novel data processing methods, can augment the information content in three-dimensional (3D) reconstructions from projections taken in the transmission electron microscope (TEM). In this work we present the application of simultaneous electron energy-loss spectroscopy (EELS) and energy-dispersive X-ray spectroscopy (EDS) to scanning TEM tomography. Various tools, including refined tilt alignment procedures, multivariate statistical analysis and total-variation minimization enable the 3D reconstruction of analytical tomograms, providing 3D analytical metrics of materials science samples at the nanometer scale. This includes volumetric elemental maps, and reconstructions of EDS, low-loss and core-loss EELS spectra as four-dimensional spectrum volumes containing 3D local voxel spectra. From these spectra, compositional, 3D localized elemental analysis becomes possible opening the pathway to 3D nanoscale elemental quantification.
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Affiliation(s)
- Georg Haberfehlner
- Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz, Austria.
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14
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Matsko NB, Letofsky-Papst I, Albu M, Mittal V. An analytical technique to extract surface information of negatively stained or heavy-metal shadowed organic materials within the TEM. Microsc Microanal 2013; 19:642-651. [PMID: 23570815 DOI: 10.1017/s1431927613000366] [Citation(s) in RCA: 2] [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: 06/02/2023]
Abstract
Using a series of uranyl acetate stained or platinum-palladium shadowed organic samples, an empirical analytical method to extract surface information from energy-filtered transmission electron microscopy (EFTEM) images is described. The distribution of uranium or platinum-palladium atoms, which replicate the sample surface topography, have been mathematically extracted by dividing the image acquired in the valence bulk plasmon energy region (between 20 and 30 eV) by the image acquired at the carbon K ionization edge (between 284 and 300 eV). The resulting plasmon-to-carbon ratio (PCR) image may be interpreted as a precise metal replica of the sample surface. In contrast to conventional EFTEM elemental mapping, including an absolute quantification approach, this technique can be applied to 200-600 nm thick organic samples. A combination of conventional TEM and PCR imaging allows one to detect complementary transmission and topographical information with nanometer precision of the same area of carbon-based samples. The advantages and limitations of PCR imaging are highlighted.
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15
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Duggen L, Albu M, Willatzen M, Rubahn HG. Near Infrared Photoacoustic Detection of Heptane in Synthetic Air. ACTA ACUST UNITED AC 2013. [DOI: 10.3813/aaa.918613] [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: 11/06/2022]
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16
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Rumpf K, Granitzer P, Hilscher G, Albu M, Poelt P. Magnetically interacting low dimensional Ni-nanostructures within porous silicon. Microelectron Eng 2012; 90:83-87. [PMID: 22308049 PMCID: PMC3242907 DOI: 10.1016/j.mee.2011.05.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Electrodeposition of ferromagnetic metals, a common method to fabricate magnetic nanostructures, is used for the incorporation of Ni structures into the pores of porous silicon templates. The porous silicon is fabricated in various morphologies with average pore-diameters between 40 and 95 nm and concomitant pore-distances between 60 and 40 nm. The metal nanostructures are deposited with different geometries as spheres, ellipsoids or wires influenced by the deposition process parameters. Furthermore small Ni-particles with diameters between 3 and 6 nm can be deposited on the walls of the porous silicon template forming a metal tube. Analysis of this tube-like arrangement by transmission electron microscopy (TEM) shows that the distribution of the Ni-particles is quite narrow, which means that the distance between the particles is smaller than 10 nm. Such a close arrangement of the Ni-particles assures magnetic interactions between them. Due to their size these small Ni-particles are superparamagnetic but dipolar coupling between them results in a ferromagnetic behavior of the whole system. Thus a semiconducting/ferromagnetic hybrid material with a broad range of magnetic properties can be fabricated. Furthermore this composite is an interesting candidate for silicon based applications and the compatibility with today's process technology.
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Affiliation(s)
- K. Rumpf
- Institute of Physics, Karl Franzens University Graz, Universitaetsplatz 5, A-8010 Graz, Austria
| | - P. Granitzer
- Institute of Physics, Karl Franzens University Graz, Universitaetsplatz 5, A-8010 Graz, Austria
| | - G. Hilscher
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8, 1040 Vienna, Austria
| | - M. Albu
- Institute for Electron Microscopy, University of Technology Graz, Steyrergasse 17, A-8010 Graz, Austria
| | - P. Poelt
- Institute for Electron Microscopy, University of Technology Graz, Steyrergasse 17, A-8010 Graz, Austria
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17
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Granitzer P, Rumpf K, Venkatesan M, Cabrera L, Roca A, Morales P, Poelt P, Albu M. Structural and magnetic characterization of a porous silicon/Fe3O4 composite. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/pssc.201000322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Oksdath-Mansilla G, Peñéñory AB, Albu M, Barnes I, Wiesen P, Teruel MA. CH3CH2SCH3 + OH radicals: temperature-dependent rate coefficient and product identification under atmospheric pressure of air. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1714] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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19
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Rumpf K, Granitzer P, Albu M, Poelt P. Electrochemically Fabricated Silicon/Metal Hybrid Nanosystem with Tailored Magnetic Properties. ACTA ACUST UNITED AC 2010. [DOI: 10.1149/1.3269188] [Citation(s) in RCA: 10] [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: 11/16/2022]
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20
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Granitzer P, Rumpf K, Roca AG, Morales MP, Poelt P, Albu M. Investigation of a Mesoporous Silicon Based Ferromagnetic Nanocomposite. Nanoscale Res Lett 2009; 5:374-8. [PMID: 20672039 PMCID: PMC2894348 DOI: 10.1007/s11671-009-9491-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 11/02/2009] [Indexed: 05/12/2023]
Abstract
A semiconductor/metal nanocomposite is composed of a porosified silicon wafer and embedded ferromagnetic nanostructures. The obtained hybrid system possesses the electronic properties of silicon together with the magnetic properties of the incorporated ferromagnetic metal. On the one hand, a transition metal is electrochemically deposited from a metal salt solution into the nanostructured silicon skeleton, on the other hand magnetic particles of a few nanometres in size, fabricated in solution, are incorporated by immersion. The electrochemically deposited nanostructures can be tuned in size, shape and their spatial distribution by the process parameters, and thus specimens with desired ferromagnetic properties can be fabricated. Using magnetite nanoparticles for infiltration into porous silicon is of interest not only because of the magnetic properties of the composite material due to the possible modification of the ferromagnetic/superparamagnetic transition but also because of the biocompatibility of the system caused by the low toxicity of both materials. Thus, it is a promising candidate for biomedical applications as drug delivery or biomedical targeting.
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Affiliation(s)
- P Granitzer
- Institute of Physics, Karl Franzens University Graz, Universitaetsplatz 5, 8010, Graz, Austria
| | - K Rumpf
- Institute of Physics, Karl Franzens University Graz, Universitaetsplatz 5, 8010, Graz, Austria
| | - AG Roca
- Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Ines de la Cruz 3, 28049, Cantoblanco, Madrid, Spain
| | - MP Morales
- Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Ines de la Cruz 3, 28049, Cantoblanco, Madrid, Spain
| | - P Poelt
- Institute for Electron Microscopy, University of Technology Graz, Steyrergasse 17, 8010, Graz, Austria
| | - M Albu
- Institute for Electron Microscopy, University of Technology Graz, Steyrergasse 17, 8010, Graz, Austria
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Granitzer P, Rumpf K, Poelt P, Albu M, Chernev B. The interior interfaces of a semiconductor/metal nanocomposite and their influence on its physical properties. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/pssc.200881730] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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22
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Albul A, Rada C, Albu M, Indrei LL. [Fruit consumption in a group of teenagers from Iaşi]. Rev Med Chir Soc Med Nat Iasi 2009; 113:554-557. [PMID: 21495365] [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] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
UNLABELLED A goal for the national nutritional education program is represented by the increase of fruit consumption. MATERIAL AND METHOD Using specially designed questionaries a group of 127 teenagers from two different Iaşi high schools provided date related to thei daily fruit intake. RESULTS Almost 40% of the teenagers use fresh fruits as part of their breakfast and a greater number use them as snacks (57.5%) or dessert (80.5%), with statistically insignificant differences between the two high schools. CONCLUSION The fruit intake is adequate in the studied group and the programs that promote certain food habits must take into account the existing situation.
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Affiliation(s)
- Adriana Albul
- Facultatea de Medicină, Disciplina de Igienă-Sănătatea Mediului, Universitatea de Medicină si Farmacie Gr.T.Popa Iaşi
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Abstract
A kinetic study on the reactions of the OH radical and ozone with acetylacetone (AcAc) has been performed in a 1080 L quartz glass reaction chamber using in situ FTIR spectroscopy analysis. Temperature dependent rate coefficients for the reaction of AcAc with the OH radical were determined over the temperature range 285-310 K using the relative kinetic method. The following Arrhenius expression was derived: k = 3.35 x 10(-12) exp((983 +/- 130)/T) cm3 molecule(-1) s(-1), where the indicated error is the two least-squares deviation. A rate coefficient (in units of cm3 molecule(-1) s(-1)) of (1.03 +/- 0.31) x 10(-18) has been obtained at (298 +/- 3) K for the reaction of ozone with AcAc. A product investigation on the gas-phase reaction of OH radical with AcAc was conducted in a 405 L borosilicate glass chamber using in situ FTIR spectroscopy to monitor reactants and products. Methylglyoxal, acetic acid, peroxy acetic nitrate (PAN) were positively identified as products with molar yields of (20.8 +/- 4.5)%, (16.9 +/- 3.4)%, and (2.0 +/- 0.5)%, respectively. From the residual infrared spectrum the main products are attributed to 2,3,4-pentantrione (CH3-CO-CO-CO-CH3) and its hydrated analogue pentan-2,3-dione-4-diol (CH3-CO-CO-C(OH)2-CH3). Based on the observed products, a simplified mechanism for the reaction of the OH radical with AcAc is proposed.
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Affiliation(s)
- Shouming Zhou
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Science, Peking University, 100871 Beijing, China
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24
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Abstract
The Y0.67Ca0.33Mn1-yAlyO3 system with y � 0.2, crystallizes in an orthorhombic type structure having Pnma space group. The La1-xPbxMnO3 perovskites with 0.24 � x 0.40 have a rhombohedral structure of R 3c�type. The Y0.67Ca0.33Mn1-yAlyO3 samples show a mictomagnetic type behaviour. The analysis of charge compensation mechanism suggests that the number of oxygen vacancies increases with Al content. A semiconducting type behaviour was also shown. The contributions of double exchange mechanism to magnetic ordering in La1-xPbxMnO3 increase as the lead content is higher. A nearly ferromagnetic type ordering was shown for the sample with x=0.4. The number of Mn4+ ions fits well with the Pb2+ ones, suggesting that the change in Mn valence state is the dominant mechanism for charge compensation. A transition from metallic to semiconducting type behaviour is shown at temperatures by@130 K lower than the Curie points. Magnetoresistivities up to @ 50 % were determined in fields of 60�70 kOe.
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Zhou S, Barnes I, Zhu T, Klotz B, Albu M, Bejan I, Benter T. Product study of the OH, NO3, and O3 initiated atmospheric photooxidation of propyl vinyl ether. Environ Sci Technol 2006; 40:5415-21. [PMID: 16999119 DOI: 10.1021/es0605422] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A product study is reported on the gas-phase reactions of OH and NO3 radicals and ozone with propyl vinyl ether (PVE). The experiments were performed in a 405 L borosilicate glass chamber in synthetic air at 298 +/- 3 K using long path in situ FTIR spectroscopy for the analysis of the reactants and products. In the presence of NO(x) (NO + NO2) the main products for the OH-radical initiated oxidation of PVE were propylformate and formaldehyde with molar formation yields of 78.6 +/- 8.8% and 75.9 +/- 8.4%, respectively. In the absence of NO(x) propylformate and formaldehyde were formed with molar formation yields of 63.0 +/- 9.0% and 61.3 +/- 6.3%, respectively. In the reaction of NO3 radicals with PVE propylformate 52.7 +/- 5.9% and formaldehyde 55.0 +/- 6.3% were again observed as major products. The ozonolysis of PVE led to the production of propylformate, formaldehyde, hydroxyperoxymethyl formate (HPMF; HC(O)OCH2OOH), and CO with molar formation yields of 89.0 +/- 11.4%, 12.9 +/- 4.0%, 13.0 +/- 3.4%, and 10.9 +/- 2.6%, respectively. The formation yield of OH radicals in the ozonolysis of PVE was estimated to be 17 +/- 9%. Simple atmospheric degradation mechanisms are postulated to explain the formation of the observed products.
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Affiliation(s)
- Shouming Zhou
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Science, Peking University, 100871 Beijing, China
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26
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Albu M, Barnes I, Becker KH, Patroescu-Klotz I, Mocanu R, Benter T. Rate coefficients for the gas-phase reaction of OH radicals with dimethyl sulfide: temperature and O2partial pressure dependence. Phys Chem Chem Phys 2006; 8:728-36. [PMID: 16482313 DOI: 10.1039/b512536g] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [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: 12/15/2022]
Abstract
Rate coefficients for the gas-phase reaction of hydroxyl (OH) radicals with dimethyl sulfide (CH(3)SCH(3), DMS) have been determined using a relative rate technique. The experiments were performed under different conditions of temperature (250-299 K) and O(2) partial pressure (approximately 0 Torr O(2)-380 Torr O(2)), at a total pressure of 760 Torr bath gas (N(2) + O(2)), in a 336 l reaction chamber, using long path in situ Fourier transform (FTIR) absorption spectroscopy to monitor the disappearance rates of DMS and the reference compounds (ethene, propene and 2-methylpropene). OH was produced by the photolysis of H(2)O(2). The following Arrhenius expressions adequately describe the rate coefficients as a function of temperature (units are cm(3) molecule(-1) s(-1)): k = (1.56 +/- 0.20) x 10(-12) exp[(369 +/- 27)/T], for approximately 0 Torr O(2); (1.31 +/- 0.08) x 10(-14) exp[(1910 +/- 69)/T], for 155 Torr O(2); (5.18 +/- 0.71) x 10(-14) exp[(1587 +/- 24)/T], for 380 Torr O(2). The results are compared with previous investigations.
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Affiliation(s)
- Mihaela Albu
- Bergische Universität Wuppertal, Physikalische Chemie/FB C, Gauss Strasse 20, D-42097 Wuppertal, Germany
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27
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Albu A, Indrei LL, Gavăt V, Petrariu FD, Albu M. [Specifics of food intake by schoolchildren in the rural areas of Moldova]. Rev Med Chir Soc Med Nat Iasi 2005; 109:153-7. [PMID: 16607846] [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] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
149 schoolchildren, 14-15 years old, from 4 rural communities pending on 4 different Moldova counties have been investigated using the one day questionnaire technique. From the entire studied group, only 7.4% are do not eat breakfast before attending school. 35.5% of the schoolchildren consider their sugar intake to be excessive, without taking into account the sugar major role in nervous cell function. The average daily intake for fresh fruits, vegetables and milk is in most cases adequate, but significant differences are present between the communities, related with the socio-economic status of the families and, also, with nutritional.
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Affiliation(s)
- Adriana Albu
- Universitatea de Medicină şi Farmacie Gr T Popa Iaşi, Facultatea de Medicină, Disciplina de Igienă
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Indrei LL, Albu A, Albu M, Dănilă L, Foia I. [Assessment of food intake in rural area school children]. Rev Med Chir Soc Med Nat Iasi 2003; 107:618-21. [PMID: 14756073] [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] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Children food intake is influenced by family nutritional habits and economic status. According to the results of our survey, only 54.8% of the children have taken their breakfast, although all of them recognize the importance of this meal. 9.6% of the children are not using fresh fruits and vegetables in their diets, even if these are the main sources of vitamin C. Regarding the milk consumption, most of the children use this food item once (35.5%) or twice (19.4%) a day and only 16.1% occasionally. Although most of the children (93.5%) know that excessive salt intake represents a risk factor for their health, 87.1% have preferences for salted and spiced foods. Under the influence of advertising, certain changes in the nutritional habits have been noticed; instead of traditional snacks, children are more attracted to fast-food type snacks.
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Affiliation(s)
- L L Indrei
- Disciplina de Igiena Alimentaţiei, Facultatea de Medicină Stomatologică, Universitatea de Medicină şi Farmacie Gr.T. Popa Isşi
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Albu A, Indrei LL, Albu M, Dănilă L. [Effect of environmental factors on high school children's health ]. Rev Med Chir Soc Med Nat Iasi 2003; 107:622-6. [PMID: 14756074] [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] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
We studied 78 teenagers from Iaşi Pedagogic High School. Body mass index values are mainly (83.3%) normal. 60.3% of the teenagers are coming from rural areas, but there are no significant differences between children coming from urban and rural areas. The frequency of families with more than 5 children in the urban areas is very small (1.3%), but in the rural areas this frequency is more than 10 times higher (15.4%). Due to this factor, the per capita income is reduced in the rural areas. Nutrition is a major problem in both urban and rural areas, due to unbalances food intake.
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Affiliation(s)
- Adriana Albu
- Disciplina de Igienă, Facultatea de Medicină, Universitatea de Medicină şi Farmacie Gr.T. Popa Iaşi
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Albu A, Indrei LL, Albu M. [Professional guidance problems in spastic hemiparesis school children]. Rev Med Chir Soc Med Nat Iasi 2002; 107:376-9. [PMID: 12638295] [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] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
People with physical handicap adapt themselves with more difficulties to professions that require manual abilities. For these youngsters, the professional guidance plays a major role. Their desire is to become independent from the social point of view, independent which is linked with a professional activity. If the youngsters with physical handicaps are correctly orientated, they become socially independent and they perform their professional duties with great correctness. In order to fulfill this goal we must understand the nature of the motric problems. This knowledge is obtained by using a series of tests that allows us to evaluate the degree of motric handicap. The physical difficiency, followed by the integration in a special school, may result in personality problems. Briefly, the motric handicap problem must be discussed in a complex, following medical aspects but also professional, psychic and social aspects.
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Affiliation(s)
- Adriana Albu
- Facultatea de Medicină, Universitatea de Medicină şi Farmacie Gr.T. Popa Iaşi
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Bilba D, Bilba N, Albu M. KINETICS OF CADMIUM ION SORPTION ON ION EXCHANGE AND CHELATING RESINS. Solvent Extraction and Ion Exchange 1999. [DOI: 10.1080/07366299908934665] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Albu A, Vartolomei C, Indrei LL, Gavăt V, Albu M, Tetraru M. [The problems of self-image formation in children with motor deficiencies]. Rev Med Chir Soc Med Nat Iasi 1998; 102:109-13. [PMID: 10756856] [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] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Self-image is a representation that each person has on its own body. The personality of an individual develops through progressive knowledge of its own body. Children with motor deficiencies have a modified self-image. For the evaluation of self-image a 1 to 10 self-assessment scale for three items (smart, resourceful, beautiful), and two time periods (now and in the future) was used. As to the dynamic components, the area "locus of control" showed significant positive differences between present and future situations (an increase from 22.1% to 56.5% for smart item, from 35.9% to 65.5% for resourceful item and only a small variation from 30.5% to 37.4% for handsome item, regarding the high marks self-assentiment).
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Affiliation(s)
- A Albu
- Disciplina de Igienă, Facultatea de Medicină, Universitatea de Medicină şi Farmacie Gr. T. Popa, Iaşi
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Baciu I, Felegean A, Maghiar TT, Hozan C, Albu M. Effects of thymectomy on blood neutrophils phagocytic activity and phagocytic response in mice. Rom J Physiol 1996; 33:75-81. [PMID: 9117340] [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] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The role of the thymus in maintenance of the basal phagocytosis of blood neutrophils and eliciting the phagocytic response, induced by i.v. Escherichia coli, was studied in 9 NMRI thymectomized and in 12 control mice. Thymectomy depresses the percentage of phagocyting neutrophils from 70.91 +/- 0.9 (mean +/- SEM) in controls, to 61.49 +/- 2.33 in the thymectomized rats. Phagocytic activity, as assessed by the number of bacteria engulfed by 100 neutrophils, was also lower in thymectomized mice (114.42 +/- 7.52) than in controls (163.71 +/- 4.53). A phagocytic response to i.v. Escherichia coli could nevertheless be noted in thymectomized mice, their phagocytic activity rising from the basal activity of 114.42 +/- 7.52 to 142.19 +/- 5.40 three hours after injection of Escherichia coli, while in control animals this activity rose from 163.71 +/- 4.53 to 216.46 +/- 12.91. These results may, at least partially, explain the recurrent infections and the septicemia occurring in children with Down's syndrome. It is suggested that the thymus, as an endocrine organ, may be involved in maintaining the basal phagocytic activity of blood neutrophils, while the phagocytic response is modulated by extrathymic mechanisms.
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Affiliation(s)
- I Baciu
- University of Oradea, Center of Physiological Research, Cluj-Napoca, Romania
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Baciu I, Tomuş L, Cojocaru A, Felegean A, Albu M. Reticulin-M, an antianaphylactic peptide secreted by reticulo-endothelial system. Rom J Physiol 1993; 30:183-92. [PMID: 7582931] [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] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
I. Moldovan (1923) demonstrated in the blood ultrafiltrate from anaphylactically prepared guinea pigs, which believed to anaphylactic shock, or which were previously injected with coloidal substances as India ink to stimulate the RES, an antianaphylactic principle named Reticulin-M(R). Authors extracted R from organs rich in RES with acetone, established their, peptidic nature and tested it on anaphylactic prepared guinea pig uterine horns in vitro. The peptides were fractioned by high voltage paper electrophoresis. The fractions were cut up in four groups, eluted and tested. The second basic group was identified as active and concentrated by acetone, recipitation. In conclusion several techniques were used to obtain, to test, to isolate and to concentrate R, a natural antianaphylactic peptidic factor, which may be a cytokine.
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Affiliation(s)
- I Baciu
- Center of Physiological Recherch Univ. of Oradea
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Niţurad A, Albu M, Alexandrescu L, Mihăilescu R, Brumaru O, Carp C. [The influence of a sanatorium cure on neuroses as a function of the clinical form and of the dominant syndromes]. Rev Med Interna Neurol Psihiatr Neurochir Dermatovenerol Neurol Psihiatr Neurochir 1988; 33:295-308. [PMID: 3255157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Tănase C, Poiană C, Vaida F, Bicică V, Stoleru L, Albu M, Moscalu G, Gavrilescu M, Bejan O, Pşegalinschi N. [Results of short-term chemotherapy in Galaţi County 4 years after completion of treatment]. Rev Ig Bacteriol Virusol Parazitol Epidemiol Pneumoftiziol Pneumoftiziol 1986; 35:279-81. [PMID: 3027870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Baraneţchi C, Vaida F, Dragoş F, Albu M, Patraşcov N. [Comparative evolution of the incidence of bronchopulmonary tuberculosis and bronchopulmonary cancer (data of the TB dispensary No. 1 in Galaţi)]. Rev Ig Bacteriol Virusol Parazitol Epidemiol Pneumoftiziol Pneumoftiziol 1982; 31:201-4, 226. [PMID: 6296974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Over a period of 10 years a decrease was noted in the area of the Tuberculosis Dispensary of the Galatzi District, of the incidence through tuberculosis of the adult by approximately 50%, and an increase of the pulmonary cancer incidence three fold. The incidence curves of these two diseases, which were far apart 10 years ago, are much nearer now, and it may be presumed that in a not too remote future they will cross each other. The pneumophysiology network should be prepared further to face the increasing flow of patients with non-tuberculous diseases. With this view physicians should be re-cycled, and various types of specialists should be trained for cytologic diagnosis, and the technical equipment of antituberculous hospitals should be updated.
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Patraşcov N, Vaida F, Albu M, Dragoş F. [Aspects of the incidence, temporary work incapacity and disability due to tuberculosis in the Galaţi district]. Rev Ig Bacteriol Virusol Parazitol Epidemiol Pneumoftiziol Pneumoftiziol 1980; 29:125-7. [PMID: 6252595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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