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Bartczak N, Kowalczyk J, Tomala R, Stefanski M, Szymański D, Ptak M, Stręk W, Szustakiewicz K, Kurzynowski T, Szczepański Ł, Junka A, Gorczyca D, Głuchowski P. Effect of the Addition of Graphene Flakes on the Physical and Biological Properties of Composite Paints. Molecules 2023; 28:6173. [PMID: 37630425 PMCID: PMC10458452 DOI: 10.3390/molecules28166173] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 08/27/2023] Open
Abstract
In this study, graphene flakes were obtained using an electrolytic method and characterized using X-ray diffraction (XRD), Raman and FTIR spectroscopy, scanning and transmission electron microscopy (SEM/TEM). Graphene-based composites with varying concentrations of 0.5%, 1% and 3% by weight were prepared with acrylic paint, enamel and varnish matrices. The mechanical properties were evaluated using micro-hardness testing, while wettability and antimicrobial activity against three pathogens (Staphylococcus aureus 33591, Pseudomonas aeruginosa 15442, Candida albicans 10231) were also examined. The results indicate that the addition of graphene flakes significantly enhances both the mechanical and antimicrobial properties of the coatings.
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Affiliation(s)
- Natalia Bartczak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PL-50422 Wroclaw, Poland; (J.K.); (R.T.); (M.S.); (D.S.); (M.P.); (W.S.)
- Faculty of Chemistry, Wroclaw University of Science and Technology, PL-50370 Wroclaw, Poland;
| | - Jerzy Kowalczyk
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PL-50422 Wroclaw, Poland; (J.K.); (R.T.); (M.S.); (D.S.); (M.P.); (W.S.)
| | - Robert Tomala
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PL-50422 Wroclaw, Poland; (J.K.); (R.T.); (M.S.); (D.S.); (M.P.); (W.S.)
| | - Mariusz Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PL-50422 Wroclaw, Poland; (J.K.); (R.T.); (M.S.); (D.S.); (M.P.); (W.S.)
| | - Damian Szymański
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PL-50422 Wroclaw, Poland; (J.K.); (R.T.); (M.S.); (D.S.); (M.P.); (W.S.)
| | - Maciej Ptak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PL-50422 Wroclaw, Poland; (J.K.); (R.T.); (M.S.); (D.S.); (M.P.); (W.S.)
| | - Wiesław Stręk
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PL-50422 Wroclaw, Poland; (J.K.); (R.T.); (M.S.); (D.S.); (M.P.); (W.S.)
| | - Konrad Szustakiewicz
- Faculty of Chemistry, Wroclaw University of Science and Technology, PL-50370 Wroclaw, Poland;
| | - Tomasz Kurzynowski
- Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, PL-50370 Wroclaw, Poland; (T.K.); (Ł.S.)
| | - Łukasz Szczepański
- Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, PL-50370 Wroclaw, Poland; (T.K.); (Ł.S.)
| | - Adam Junka
- Platform for Unique Models Application, Wroclaw Medical University, PL-50367 Wroclaw, Poland;
| | - Damian Gorczyca
- Medical Department, Lazarski University, PL-02662 Warsaw, Poland;
| | - Paweł Głuchowski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PL-50422 Wroclaw, Poland; (J.K.); (R.T.); (M.S.); (D.S.); (M.P.); (W.S.)
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2
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Stefanski M, Gonçalves JM, Strek W. Broad Luminescence Generated by IR Laser Excitation from CsPbBr 3:Yb 3+ Perovskite Ceramics. Molecules 2023; 28:5324. [PMID: 37513198 PMCID: PMC10386396 DOI: 10.3390/molecules28145324] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/08/2023] [Accepted: 07/09/2023] [Indexed: 07/30/2023] Open
Abstract
This paper demonstrates the generation of broadband emission in the visible and infrared ranges induced by a concentrated beam of infrared radiation from CsPbBr3 ceramics doped with Yb3+ ions. The sample was obtained by the conventional solid-state reaction method, and XRD measurements confirmed the phase purity of the material crystallizing in the orthorhombic system. Spectroscopic measurements required further sample preparation in the form of ceramics using a high-pressure press. The research showed that as the excitation power increases, the emission intensity does not increase linearly from the beginning of the experiment. Irradiation of the material results in the accumulation of the delivered energy. Absorption of a sufficient number of photons triggers avalanche emission. It was found that the most intense luminescence is produced in a vacuum. Changes in conductivity were also observed, where the excitation was able to lower the resistivity of the material and it was highly dependent on the excitation power. The mechanism responsible for the generation of the observed phenomenon involving intervalence charge transfer (IVCT) transitions has been postulated.
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Affiliation(s)
- Mariusz Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - João Marcos Gonçalves
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - Wieslaw Strek
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
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3
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Grabowska A, Kowalczyk J, Tomala R, Ptak M, Małecka M, Wędzyńska A, Stefanski M, Stręk W, Głuchowski P. Optimization of the Electrochemical Method of Obtaining Graphene Nanoplatelets (GNPs). Materials (Basel) 2023; 16:2188. [PMID: 36984068 PMCID: PMC10057930 DOI: 10.3390/ma16062188] [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: 01/20/2023] [Revised: 02/22/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Graphene nanoplatelets (GNPs) were prepared using the electrolytic exfoliation method on graphite foil in an ammonium sulfate solution. A series of experiments were conducted in order to optimize the production of the flakes by varying the pH of the solution, applied voltage and current, duration of electrolysis, temperature in the electrolytic system, and type and duration of the ultrasound interaction. The quality of the produced graphene nanoplatelets was analyzed using X-ray diffraction, Raman and IR spectroscopy, and TEM.
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Affiliation(s)
- Adrianna Grabowska
- Faculty of Chemistry, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - Jerzy Kowalczyk
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - Robert Tomala
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - Maciej Ptak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - Małgorzata Małecka
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - Anna Wędzyńska
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - Mariusz Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - Wiesław Stręk
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - Paweł Głuchowski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
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4
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Gonçalves JM, Stefanski M, Tomala R, Musialek A, Strek W. Laser induced white emission generation from La 1-xNd xAlO 3 nanocrystals. Dalton Trans 2023; 52:2073-2079. [PMID: 36692330 DOI: 10.1039/d2dt03553g] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The synthesis and structural characteristics of nanocrystalline LaAlO3 perovskites doped with different concentrations of Nd3+ ions are reported. Their excitation and Stokes emission spectra, in which significant concentration quenching was observed, were recorded and characterized. The measurements of anti-Stokes laser induced white emission (LIWE) spectra were also performed. It was found that the LIWE intensity increased exponentially with the excitation laser power above the excitation threshold. In particular, the concentration and pressure dependences of the LIWE spectra of La1-xNdxAlO3 were investigated. Despite the pronounced concentration quenching observed in the Stokes emission, no such effect could be observed in the anti-Stokes one. A possible inter-valence charge transfer (IVCT) mechanism for the white emission, in which different bands that were observed correspond to different valences of Nd, is proposed.
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Affiliation(s)
- João Marcos Gonçalves
- Institute of Low Temperature and Structure Research, Polish Academy of Science, Okolna 2, 50-422 Wroclaw, Poland.
| | - Mariusz Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Science, Okolna 2, 50-422 Wroclaw, Poland.
| | - Robert Tomala
- Institute of Low Temperature and Structure Research, Polish Academy of Science, Okolna 2, 50-422 Wroclaw, Poland.
| | - Agata Musialek
- Institute of Low Temperature and Structure Research, Polish Academy of Science, Okolna 2, 50-422 Wroclaw, Poland.
| | - Wieslaw Strek
- Institute of Low Temperature and Structure Research, Polish Academy of Science, Okolna 2, 50-422 Wroclaw, Poland.
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Wytrych P, Utko J, Stefanski M, Kłak J, Lis T, John Ł. Synthesis, Crystal Structures, and Optical and Magnetic Properties of Samarium, Terbium, and Erbium Coordination Entities Containing Mono-Substituted Imine Silsesquioxane Ligands. Inorg Chem 2023; 62:2913-2923. [PMID: 36716237 PMCID: PMC9930112 DOI: 10.1021/acs.inorgchem.2c04371] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mono-substituted cage-like silsesquioxanes of the T8-type can play the role of potential ligands in the coordination chemistry. In this paper, we report on imine derivatives as ligands for samarium, terbium, and erbium cations and discuss their efficient synthesis, crystal structures, and magnetic and optical properties. X-ray analysis of the lanthanide coordination entities [MCl3(POSS)3]·2THF [M = Er3+ (3), Tb3+ (4), Sm3+ (5)] showed that all three compounds crystallize in the same space group with similar lattice parameters. All compounds contain an octahedrally coordinated metal atom, and additionally, 3 and 5 structures are strictly isomorphous. However, surprisingly, there are two different molecules in the crystal structure of the terbium coordination entity 4, monomer (sof 65%) and dimer (sof 35%), with one and two metal centers. Absorption measurements of the investigated materials recorded at 300 K showed that regardless of the lanthanide involved, their energy band gap equals 2.7 eV. Moreover, the analogues containing Tb3+ and Sm3+ exhibit luminescence typical of these rare earth ions in the visible and infrared spectral range, while the compound with Er3+ does not generate any emission. Direct current variable-temperature magnetic susceptibility measurements on polycrystalline samples of 3-5 were performed between 1.8 and 300 K. The magnetic properties of 3 and 4 are dominated by the crystal field effect on the Er3+ and Tb3+ ions, respectively, hiding the magnetic influence between the magnetic cations of adjacent molecules. Complex 5 exhibits a nature typical for the paramagnetism of the samarium(III) cation.
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Affiliation(s)
- Patrycja Wytrych
- Faculty
of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383Wrocław, Poland
| | - Józef Utko
- Faculty
of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383Wrocław, Poland
| | - Mariusz Stefanski
- Institute
of Low Temperature and Structure Research, Polish Academy of Sciences, 2 Okólna, 50-422Wrocław, Poland
| | - Julia Kłak
- Faculty
of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383Wrocław, Poland
| | - Tadeusz Lis
- Faculty
of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383Wrocław, Poland
| | - Łukasz John
- Faculty
of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383Wrocław, Poland,
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6
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Zienkiewicz JA, Kałduńska K, Fedoruk K, Barros dos Santos AJ, Stefanski M, Paraguassu W, Muzioł TM, Ptak M. Luminescence and Dielectric Switchable Properties of a 1D (1,1,1-Trimethylhydrazinium)PbI 3 Hybrid Perovskitoid. Inorg Chem 2022; 61:20886-20895. [PMID: 36520079 PMCID: PMC9795545 DOI: 10.1021/acs.inorgchem.2c03287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The synthesis and investigation of the physicochemical properties of a novel one-dimensional (1D) hybrid organic-inorganic perovskitoid templated by the 1,1,1-trimethylhydrazinium (Me3Hy+) cation are reported. (Me3Hy)[PbI3] crystallizes in the hexagonal P63/m symmetry and undergoes two phase transitions (PTs) during heating (cooling) at 322 (320) and 207 (202) K. X-ray diffraction data and temperature-dependent vibrational studies show that the second-order PT to the high-temperature hexagonal P63/mmc phase is associated with a weak change in entropy and is related to weak structural changes and different confinement of cations in the available space. The second PT to the low-temperature orthorhombic Pbca phase that corresponds to the high change in entropy and dielectric switching is associated with an ordering of the trimethylhydrazinium cations, re-arrangement and strengthening of hydrogen bonds, and slightly shifted lead-iodide octahedral chains. The high-pressure Raman data revealed two additional PTs, one between 2.8 and 3.2 GPa, related to the symmetry decrease, ordering of the cations, and inorganic chain distortion, and the other in the 6.4-6.8 GPa range related to the partial and reversible amorphization. Optical studies revealed that (Me3Hy)[PbI3] has a wide band gap (3.20 eV) and emits reddish-orange excitonic emission at low temperatures with an activation energy of 65 meV.
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Affiliation(s)
- Jan. A. Zienkiewicz
- Institute
of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422Wrocław, Poland,
| | - Karolina Kałduńska
- Department
of Biomedical and Polymer Chemistry, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100Toruń, Poland
| | - Katarzyna Fedoruk
- Institute
of Physics, Wrocław University of
Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370Wrocław, Poland
| | - Antonio J. Barros dos Santos
- Department
of Physics, Federal University of Pará, Campus do Guamá, Rua Augusto
Corrêa 01, Belém, 66075110Pará, Brazil
| | - Mariusz Stefanski
- Institute
of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422Wrocław, Poland
| | - Waldeci Paraguassu
- Department
of Physics, Federal University of Pará, Campus do Guamá, Rua Augusto
Corrêa 01, Belém, 66075110Pará, Brazil
| | - Tadeusz M. Muzioł
- Department
of Inorganic and Coordination Chemistry, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100Toruń, Poland
| | - Maciej Ptak
- Institute
of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422Wrocław, Poland
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7
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Wytrych P, Utko J, Kłak J, Ptak M, Stefanski M, Lis T, Ejfler J, John Ł. Synthesis, Crystal Structures, and Spectroscopic Properties of Novel Gadolinium and Erbium Triphenylsiloxide Coordination Entities. Molecules 2021; 27:molecules27010147. [PMID: 35011379 PMCID: PMC8746333 DOI: 10.3390/molecules27010147] [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: 12/06/2021] [Revised: 12/20/2021] [Accepted: 12/23/2021] [Indexed: 11/16/2022]
Abstract
In alkali metal and lanthanide coordination chemistry, triphenylsiloxides seem to be unduly underappreciated ligands. This is as surprising as that such substituents play a crucial role, among others, in stabilizing rare oxidation states of lanthanide ions, taking a part of intramolecular and molecular interactions stabilizing metal-oxygen cores and many others. This paper reports the synthesis and characterization of new lithium [Li4(OSiPh3)4(THF)2] (1), and sodium [Na4(OSiPh3)4] (2) species, which were later used in obtaining novel gadolinium [Gd(OSiPh3)3(THF)3]·THF (3), and erbium [Er(OSiPh3)3(THF)3]·THF (4) configuration, it can result in res were determined for all 1-4 compounds, and in addition, IR, Raman, absorption spectroscopy studies were conducted for 3 and 4 lanthanide compounds. Furthermore, direct current (dc) variable-temperature magnetic susceptibility measurements on polycrystalline samples of 3 and 4 were carried out in the temperature range 1.8-300 K. The 3 shows behavior characteristics for the paramagnetism of the Gd3+ ion. In contrast, the magnetic properties of 4 are dominated by the crystal field effect on the Er3+ ion, masking the magnetic interaction between magnetic centers of neighboring molecules.
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Affiliation(s)
- Patrycja Wytrych
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
| | - Józef Utko
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
| | - Julia Kłak
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
| | - Maciej Ptak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 2 Okólna, 50-422 Wrocław, Poland; (M.P.); (M.S.)
| | - Mariusz Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 2 Okólna, 50-422 Wrocław, Poland; (M.P.); (M.S.)
| | - Tadeusz Lis
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
| | - Jolanta Ejfler
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
| | - Łukasz John
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
- Correspondence:
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8
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Ciupa-Litwa A, Zienkiewicz JA, Stefanski M, Ptak M, Majchrowski A, Chrunik M. Vibrational and optical studies of a nonlinear optical crystal, Cs 2Bi 2O(Ge 2O 7). Spectrochim Acta A Mol Biomol Spectrosc 2021; 259:119816. [PMID: 33989973 DOI: 10.1016/j.saa.2021.119816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 04/02/2021] [Accepted: 04/08/2021] [Indexed: 06/12/2023]
Abstract
Single crystals of a non-centrosymmetric and polar Cs2Bi2O(Ge2O7) compound were grown from melt. This material was characterized by polarized Raman scattering at room temperature. The comparison to the polycrystalline IR and Raman spectra has been made and assignment of all observed modes to the respective vibrations and their symmetry has been proposed. Our results show that this crystal is promising SRS-active nonlinear optical material for up- and down-Raman laser-frequency converters with the most intense lasing line at 481 cm-1. Optical studies show that Cs2Bi2O(Ge2O7) exhibits intense absorption bands with peaks maxima at 260 and 293 nm (77 K) typical for 1S0→1,3P1 transitions of Bi3+ ions, which are parity-allowed due to spin-orbit coupling as well as unexpected band centered at 360 nm that was assigned to intervalence charge transfer transition.
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Affiliation(s)
- Aneta Ciupa-Litwa
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław, Poland.
| | - Jan Albert Zienkiewicz
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław, Poland
| | - Mariusz Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław, Poland
| | - Maciej Ptak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław, Poland
| | - Andrzej Majchrowski
- Institute of Applied Physics, Military University of Technology, Kaliskiego 2, 00-908 Warszawa, Poland
| | - Maciej Chrunik
- Institute of Applied Physics, Military University of Technology, Kaliskiego 2, 00-908 Warszawa, Poland
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Strek W, Stefanski M, Hanulia T, Tomala R, Wiewiorski P. Laser induced visible and infrared emission of a tungsten filament. Opt Express 2021; 29:27291-27297. [PMID: 34615147 DOI: 10.1364/oe.433852] [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] [Received: 06/10/2021] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
The measurements of laser induced emission (LIE) of a tungsten filament upon irradiation with the focused beam of a CW IR laser diode are reported. It was found that the emission occurred in visible and infrared range. The influence of the applied DC electric field significantly affected the intensity of LIE of the tungsten filament. The origin of LIE is discussed in terms of multiphoton ionization of tungsten W+ atoms assisted by light emission due to the intervalence charge transfer in the tungsten hybrid domain (W, W+).
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10
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Stefanski M, Monnier J, Le Guern A, Visseaux L, Ehret M, Colomb M, Jeudy G, Vourch M, Le Duff F, Norberciak L, Baroudjian B, Bernigaud C, Perea-Villacorta R, Mallet S, Debarbieux S, Perrot J, Grange F, Modiano P, Bahadoran P. Activité de microscopie confocale in vivo en France : étude observationnelle prospective multicentrique. Ann Dermatol Venereol 2020. [DOI: 10.1016/j.annder.2020.09.261] [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: 11/28/2022]
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11
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Stefanski M, Duretz C, Bataille M, Lamiaux M, Le Guern A, Greliak A, Modiano P. Un cas de dermatite herpétiforme résistante traitée par rituximab. Ann Dermatol Venereol 2020. [DOI: 10.1016/j.annder.2020.09.310] [Citation(s) in RCA: 1] [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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12
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Stefanski M, Tomala R, Strek W. Studies of graphene influence on the laser induced white emission spectra of Sr 2CeO 4/graphene flake composites. Dalton Trans 2020; 49:9130-9136. [PMID: 32578638 DOI: 10.1039/d0dt01405b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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 Stokes and anti-Stokes emission spectra generated from Sr2CeO4/graphene flake composites were investigated. The excitation and emission spectra, decay profiles and quantum efficiency of the studied materials were collected. It was found that the addition of graphene flakes (GFs) significantly affects spectroscopic properties. In particular, the anti-Stokes laser induced white emission spectra were analyzed as a function of excitation laser power, and ambient atmospheric pressure. The influence of graphene flakes concentration on laser induced photocurrent was investigated. The color of their emission significantly differs from the color of other tested composites. In particular, the impact of graphene concentration on the investigated features will be presented and mechanisms responsible for the observed effects will be discussed.
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Affiliation(s)
- Mariusz Stefanski
- Institute of Low Temperature and Structure Research Polish Academy of Sciences, 50-422 Wroclaw, Poland.
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13
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Stefanski M, Lukaszewicz M, Hreniak D, Strek W. Impact of the synthesis procedure on the spectroscopic properties of anti-Stokes white emission obtained from Sr2CeO4 phosphor. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2019.111855] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Stefanski M, Grzeszkiewicz K, Ptak M, Hreniak D, Strek W. Structural and optical characterization of RbLaP 4O 12:Ln 3+ (Ln 3+ = Ce 3+, Nd 3+, Tm 3+, or Yb 3+). J Chem Phys 2019; 150:094706. [PMID: 30849893 DOI: 10.1063/1.5085343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, for the first time, detailed structural and optical characterization of RbLaP4O12 doped with different concentrations of Ce3+, Nd3+, Tm3+, or Yb3+ ions is reported. The samples were obtained via a precipitation technique. Their structural characterization was performed using X-ray diffraction (XRD), and infrared and Raman spectroscopies. Following XRD data, the unit cell parameters of host lattices were calculated using Rietveld refinement. It was found that an increase in the dopant content leads to a decrease in the unit cell volume. The optical characterization of RbLaP4O12:Ln3+ was carried out by collecting absorption and emission spectra, as well as luminescence decay profiles. Following absorption spectra, the energy band gap of the studied matrix was determined. It was found that the broad absorption band located in the ultra-violet range, in most cases ascribed to charge transfer or f-d transitions, is in fact related to the absorption of the host lattice. The analysis of luminescence properties allowed us to investigate possible ways of depopulation emission levels of impurities.
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Affiliation(s)
- M Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - K Grzeszkiewicz
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - M Ptak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - D Hreniak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - W Strek
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
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Stefanski M, Lukaszewicz M, Hreniak D, Strek W. Laser induced white emission generated by infrared excitation from Eu 3+:Sr 2CeO 4 nanocrystals. J Chem Phys 2018; 146:104705. [PMID: 28298121 DOI: 10.1063/1.4978237] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The laser induced white emission (LIWE) was observed from Eu3+:Sr2CeO4 nanocrystals. The samples were obtained in form of powders by the modified sol-gel route. The structure and morphology of the phosphors were investigated by powder X-ray diffraction and transmission electron microscope techniques. The intense LIWE occurred under reduced pressure and focused beam of near infrared laser excitation. The power and pressure dependencies exhibit evident threshold character typical for the avalanche effect. The photoconductivity of the Eu3+:Sr2CeO4 nanocrystals measured as a function of different powers of excitation source was analyzed.
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Affiliation(s)
- M Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - M Lukaszewicz
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - D Hreniak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - W Strek
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
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Strek W, Tomala R, Marciniak L, Lukaszewicz M, Cichy B, Stefanski M, Hreniak D, Kedziorski A, Krosnicki M, Seijo L. Broadband anti-Stokes white emission of Sr 2CeO 4 nanocrystals induced by laser irradiation. Phys Chem Chem Phys 2016; 18:27921-27927. [PMID: 27722306 DOI: 10.1039/c6cp04904d] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [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 laser induced white emission (LIWE) from Sr2CeO4 nanocrystals upon irradiation with a focused IR laser beam was investigated. It was observed to be a threshold phenomenon with its intensity increasing exponentially with the excitation power density. This process was investigated under double laser beam simultaneous excitation in the UV range leading to Stokes emission in the visible range and in the IR range leading to anti-Stokes LIWE. With increasing LIWE intensity, the Stokes emission intensity strongly decreased. The LIWE is accompanied by efficient photocurrent generation depending on laser excitation density followed by multiphoton absorption and ionization processes. Photoimpedance measurements showed a sharp increase of the dielectric constant by several orders of magnitude in the Sr2CeO4 nanocrystals during the LIWE process demonstrating a metallic-like behaviour. The mechanisms of LIWE include multiphoton absorption and ionization that lead to the creation of a coupled pair of Ce3+ and Ce4+ ions that allow for the intervalence charge transfer (IVCT) emission transitions in the white light range. A strong decrease of absorption band intensity of Sr2CeO4 with increasing LIWE intensity confirms the creation of (Ce3+, Ce4+) pairs.
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Affiliation(s)
- W Strek
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, 50-433, Poland.
| | - R Tomala
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, 50-433, Poland.
| | - L Marciniak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, 50-433, Poland.
| | - M Lukaszewicz
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, 50-433, Poland.
| | - B Cichy
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, 50-433, Poland.
| | - M Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, 50-433, Poland.
| | - D Hreniak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, 50-433, Poland.
| | - A Kedziorski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Toruń, 87-100, Poland
| | - M Krosnicki
- Institute of Theoretical Physics and Astrophysics, University of Gdańsk, Gdańsk, 80-308, Poland
| | - L Seijo
- Departamento de Quimica, Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Spain
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Stefanski M, Marciniak L, Hreniak D, Strek W. Erratum: "Influence of grain size on optical properties of Sr2CeO4 nanocrystals" [J. Chem. Phys. 142, 184701 (2015)]. J Chem Phys 2016; 144:109901. [PMID: 26979709 DOI: 10.1063/1.4943579] [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: 11/14/2022] Open
Affiliation(s)
- M Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - L Marciniak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - D Hreniak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
| | - W Strek
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland
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Marciniak L, Stefanski M, Tomala R, Hreniak D, Strek W. Synthesis and up-conversion luminescence of Er3+ and Y b3+ codoped nanocrystalline tetra- (KLaP4O12) and pentaphosphates (LaP5O14). J Chem Phys 2015; 143:094701. [DOI: 10.1063/1.4929582] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- L. Marciniak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, Poland
| | - M. Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, Poland
| | - R. Tomala
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, Poland
| | - D. Hreniak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, Poland
| | - W. Strek
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, Poland
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Affiliation(s)
- M. Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50–422 Wroclaw, Poland
| | - L. Marciniak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50–422 Wroclaw, Poland
| | - D. Hreniak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50–422 Wroclaw, Poland
| | - W. Strek
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50–422 Wroclaw, Poland
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Marciniak Ł, Bednarkiewicz A, Stefanski M, Tomala R, Hreniak D, Strek W. Near infrared absorbing near infrared emitting highly-sensitive luminescent nanothermometer based on Nd3+ to Yb3+ energy transfer. Phys Chem Chem Phys 2015; 17:24315-21. [DOI: 10.1039/c5cp03861h] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A new type of near infrared absorbing near infrared emitting (NANE) luminescent nanothermometer is presented, whose physical background relies on efficient and temperature dependent Nd3+ to Yb3+ energy transfer under 808 nm photo-excitation.
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Affiliation(s)
- Ł. Marciniak
- Institute of Low Temperature and Structure Research
- Polish Academy of Sciences
- 50-422 Wroclaw
- Poland
| | - A. Bednarkiewicz
- Institute of Low Temperature and Structure Research
- Polish Academy of Sciences
- 50-422 Wroclaw
- Poland
| | - M. Stefanski
- Institute of Low Temperature and Structure Research
- Polish Academy of Sciences
- 50-422 Wroclaw
- Poland
| | - R. Tomala
- Institute of Low Temperature and Structure Research
- Polish Academy of Sciences
- 50-422 Wroclaw
- Poland
| | - D. Hreniak
- Institute of Low Temperature and Structure Research
- Polish Academy of Sciences
- 50-422 Wroclaw
- Poland
| | - W. Strek
- Institute of Low Temperature and Structure Research
- Polish Academy of Sciences
- 50-422 Wroclaw
- Poland
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Strobel J, Spengler C, Stefanski M, Friemert B, Palm HG. [Influence of bodily constitution and physical activity on postural stability]. Sportverletz Sportschaden 2011; 25:159-66. [PMID: 21922438 DOI: 10.1055/s-0029-1246114] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
CONTEXT AND OBJECTIVE In order for balance to be maintained, the postural control system must process above all visual, vestibular and proprioceptive information and translate this input into appropriate motor responses. The influence of bodily constitution and physical activity on motor responses and thus on postural stability is still unclear. To use computerized dynamic posturography (CDP) to investigate the influence of body height, body mass index (BMI), regular sporting activity and acute maximal exercise on balance. SUBJECTS AND METHODS Eighty-four subjects completed a standardized questionnaire on their height, BMI and sporting activity. We then assessed the postural stability of the subjects. Seventeen further subjects performed a maximal exercise test on a bicycle ergometer. We used CDP and a predefined protocol to assess balance at rest, at maximal exercise and then at 5-minute intervals until recovery. RESULTS Body height and regular physical activity did not influence balance ability. By contrast, BMI and acute physical exercise had a strong effect. Immediately after maximal exercise, postural stability deteriorated by 44 % compared to the baseline level (p < 0.017). Complete recovery occurred within only 15 minutes. CONCLUSIONS Whereas body height and regular physical activity do not influence balance performance, a high BMI value and acute maximal exercise lead to a considerable decrease in postural stability. Our results can thus explain the increasing risk of injury after strenuous physical activity, especially in association with sports that require excellent balance.
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Affiliation(s)
- J Strobel
- Klinik für Unfallchirurgie und Orthopädie, Unfallchirurgische Forschungsgruppe, Bundeswehrkrankenhaus Ulm
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Abstract
Thirty-five healthy, premature infants, ranging from 30-39 weeks postconceptional age, were observed continuously for 6 to 24 hr. Behavioral state and electroencephalographic patterns were coded for each minute. Using these data, three questions regarding coding of states of sleep were addressed: What is the concordance between behavioral codes and specific EEG patterns? Does the concordance between behavioral codes and EEG patterns change with postconceptional age? What range of error can be expected when observation periods shorter than 24-hr are used to estimate the daily distribution of quiet sleep (QS) and active sleep (AS)? With behavioral codes as the standard, concordances of EEG patterns for QS and AS were 72.5 and 92.1% respectively. With EEG patterns as the standard, behavioral codes for QS and AS agreed 83.0 and 88.9%. Agreement between behavioral codes and EEG patterns for QS increased with age. Finally, variation in estimates of the daily distribution of QS and AS decreased dramatically as the length of observation increased from 3 to 24 hr.
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Affiliation(s)
- R Sahni
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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Schulze KF, Stefanski M, Masterson J, Spinnazola R, Ramakrishnan R, Dell RB, Heird WC. Energy expenditure, energy balance, and composition of weight gain in low birth weight infants fed diets of different protein and energy content. J Pediatr 1987; 110:753-9. [PMID: 3572629 DOI: 10.1016/s0022-3476(87)80019-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The effect of energy and protein intakes on energy expenditure, energy balance, and amount and relative rate of both protein and fat deposition in new tissue was investigated in 19 low birth weight infants whose mean protein and energy intakes, respectively, were 2.24 g/kg/d and 113 kcal/kg/d (formula A, n = 8), 3.6 g/kg/d and 115 kcal/kg/d (formula B, n = 5), and 3.5 g/kg/d and 149 kcal/kg/d (formula C, n = 6). The higher energy intake (formula C) but not the higher protein intake (formula B) resulted in greater energy expenditure. Both the higher protein (formula B vs formula A) and higher energy intakes (formula C vs formula B) resulted in greater weight gain secondary, in group B, to a greater absolute rate of protein deposition and, in group C, to a greater absolute rate of fat deposition. The relative composition of the new tissue deposited reflected the proportional intakes of protein and energy. The numerical value of the protein/fat ratio (g/g) of the new tissue deposited by infants fed formulas A and C, the protein contents of which were low relative to energy contents, were similar and significantly lower than the numerical value of the protein/fat ratio of the new tissue deposited by infants fed formula B, which had a higher protein content relative to energy content. These findings suggest that the composition of weight gain is related to both the absolute amounts and the proportions of dietary protein and energy; thus, both must be considered in formulation of nutritional regimens for LBW infants.
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Schulze K, Stefanski M, Masterson J, Kashyap S, Sanocka U, Forsyth M, Ramakrishnan R, Dell R. An analysis of the variability in estimates of bioenergetic variables in preterm infants. Pediatr Res 1986; 20:422-7. [PMID: 3086827 DOI: 10.1203/00006450-198605000-00009] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Estimates of average daily energy expenditure and minimal observed oxygen consumption are commonly used to characterize the energy metabolism of neonates. Yet, the errors inherent in these estimates have not been defined. Using measurements of oxygen consumption and carbon dioxide production made in healthy growing low birth weight infants during eight consecutive 3-h interfeeding epochs, we have determined the variability in the mean oxygen consumption, carbon dioxide production, respiratory quotient, total daily energy expenditure, and the minimal observed oxygen consumption among the feeding epochs. The coefficient of variation for oxygen consumption ranged from 3.1 to 9.1%, for minimal observed oxygen consumption from 3.7 to 16.7%, for carbon dioxide production from 3.3 to 7.4%, and for total daily energy expenditure from 2.9 to 7.6%. The SDs for respiratory quotient ranged from 0.008 to 0.066. From these 24-h data we have calculated the error in predicting daily estimates of the mean values for these variables if observations are made for less than 24 h. As expected, this error decreases with increasing duration of observation. These data should prove useful in the design and interpretation of investigations of neonatal energy expenditure.
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Stefanski M, Schulze K, Bateman D, Kairam R, Pedley TA, Masterson J, James LS. A scoring system for states of sleep and wakefulness in term and preterm infants. Pediatr Res 1984; 18:58-62. [PMID: 6701035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We designed and validated a system for determining the state of sleep or wakefulness in both term and preterm infants. The system is based on independent assessments of behavioral and electroencephalographic (EEG) patterns. Overall agreement between observers in coding individual behavioral patterns was 77.6%. Agreement between observers in coding EEG patterns was 87.4%. Designation of an infant's state is made by combining concurrent behavioral and EEG scores into a single two-number code. The distribution of sleep state for eight infants greater than 36 wk postconceptional age (PCA) was the following: quiet sleep (QS), 30.4%; active sleep (AS), 50.0%; indeterminate sleep (IS), 11.4%, and wakefulness (W), 7.5%. The distribution of sleep state for 15 infants less than 36 wk PCA was as follows: QS, 18.9%; AS, 52.9%; IS, 16.4%; and W, 10.5%. Our experience with the system suggests that it is useful for relating sleep state to physiologic variables during neonatal experimental studies.
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Schulze K, Stefanski M, Masterson J, James LS. Instrumentation for the continuous measurement of gas exchange and ventilation of infants during assisted ventilation. Crit Care Med 1983; 11:892-6. [PMID: 6627960 DOI: 10.1097/00003246-198311000-00011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A system of instrumentation for continuous measurement of oxygen consumption (VO2), carbon dioxide production (VCO2) and minute ventilation (V1) in human newborns on assisted ventilation is described. VO2 and VCO2 are measured by open-circuit indirect calorimetry utilizing a Servomex OA 184 differential paramagnetic oxygen analyzer and a Beckman LB 2 infrared CO2 analyzer. Minute volume is measured with a body plethysmograph. Bench performance is described, limitations of the system are defined, and sample clinical data are presented. The instrumentation can measure safely, accurately, and continuously physiologic variables in sick infants on assisted ventilation.
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Schulze K, Kairam R, Stefanski M, Sciacca R, Bateman D, Dell R, James LS. Spontaneous variability in minute ventilation oxygen consumption and heart rate of low birth weight infants. Pediatr Res 1981; 15:1111-6. [PMID: 7267185 DOI: 10.1203/00006450-198108000-00008] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Continuous measurements of minute ventilation (VI), oxygen consumption (VO2), heart rate (HR), activity, and temperature were made in eleven low birth weight infants during the interval between feedings. Significant increases in VI, VO2, and HR were noted between quiet and active sleep. (VI Active - VI Quiet/VI Quiet) X 100 = 18.4% VO2 Active - VO2 Quiet/VO2 Quiet) X 100 = 10.1% and HR Active - HR Quiet/HR Quiet) X 100 = 6.4%. Significant differences were also noted within epochs of the same state of sleep: mean slope VI versus time in epoch (t) = -156 ml/kg . min/hr, VO2 versus t. = 1.49 ml/kg . min/hr and HR versus t = -15.0 beats/min/hr. Differences between successive epochs of the same state of sleep were also observed: VI, +5.9 to 46.6%; VO2, 4.7 to 24.6%; HR, 1.0 to 9.7%. These differences were related to the length of time after feeding. These data indicate that steady state conditions do not occur in growing low birth weight infants and that the design of studies of respiration and metabolism in these infants should include continuous assessment of the state of sleep or activity and time after feeding to ensure that experimental and control periods are truly comparable.
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Schulze K, Kairam R, Stefanski M, Sciacca R, James LS. Continuous measurement of minute ventilation and gaseous metabolism of newborn infants. J Appl Physiol Respir Environ Exerc Physiol 1981; 50:1098-103. [PMID: 6785265 DOI: 10.1152/jappl.1981.50.5.1098] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A system of instrumentation for continuous measurement of gaseous metabolism and minute volume (VI) in the human newborn is described. O2 uptake and CO2 production are measured by open-circuit techniques utilizing a Servomex OA184 differential paramagnetic O2 analyzer and a BEckman LB-2 infrared CO2 analyzer. VI is measured with bias-flow pneumotachometry. Bench performance is described, methodological errors are defined, and clinical data are presented. The instrumentation is capable of safe, accurate, and continuous measurement of respiratory and metabolic variables in low-birth-weight infants.
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