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  1. Article: The Synthesis of Hydroxyapatite by Hydrothermal Process with Calcium Lactate Pentahydrate: The Effect of Reagent Concentrations, pH, Temperature, and Pressure.

    Szterner, Piotr / Biernat, Monika

    Bioinorganic chemistry and applications

    2022  Volume 2022, Page(s) 3481677

    Abstract: Hydroxyapatite and other calcium phosphates in the form of whiskers are lately widely considered as fillers for biocomposites due to their special biological and reinforcing properties. Depending on the method of synthesis, apatite whiskers of various ... ...

    Abstract Hydroxyapatite and other calcium phosphates in the form of whiskers are lately widely considered as fillers for biocomposites due to their special biological and reinforcing properties. Depending on the method of synthesis, apatite whiskers of various sizes and phase composition can be obtained. In our work, hydroxyapatite (HAp) whiskers were successfully prepared in reaction between calcium lactate pentahydrate and orthophosphoric acid. The advantage of the proposed technique is the simple but precise control of the HAp crystal morphology and high product purity which is necessary for biomedical applications. The effect of reagent concentrations, pH, reaction temperature, and pressure on HAp whiskers' morphology and composition was investigated. In the result, we obtained hydroxyapatite of different morphology such as whiskers, hexagonal rods, and nanorods. The products were characterized by SEM, XRD, and FTIR. In this work, the synthesis of HAp whiskers by direct decomposition of calcium lactate pentahydrate chelates under hydrothermal conditions was showed for the first time.
    Language English
    Publishing date 2022-03-25
    Publishing country Egypt
    Document type Journal Article
    ZDB-ID 2213020-2
    ISSN 1687-479X ; 1565-3633
    ISSN (online) 1687-479X
    ISSN 1565-3633
    DOI 10.1155/2022/3481677
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Calcination and ion substitution improve physicochemical and biological properties of nanohydroxyapatite for bone tissue engineering applications.

    Kurzyk, Agata / Szwed-Georgiou, Aleksandra / Pagacz, Joanna / Antosik, Agnieszka / Tymowicz-Grzyb, Paulina / Gerle, Anna / Szterner, Piotr / Włodarczyk, Marcin / Płociński, Przemysław / Urbaniak, Mateusz M / Rudnicka, Karolina / Biernat, Monika

    Scientific reports

    2023  Volume 13, Issue 1, Page(s) 15384

    Abstract: Nanohydroxyapatite (nanoHAP) is widely used in bone regeneration, but there is a need to enhance its properties to provide stimuli for cell commitment and osteoconduction. This study examines the effect of calcination at 1200 °C on the physicochemical ... ...

    Abstract Nanohydroxyapatite (nanoHAP) is widely used in bone regeneration, but there is a need to enhance its properties to provide stimuli for cell commitment and osteoconduction. This study examines the effect of calcination at 1200 °C on the physicochemical and biological properties of nanoHAP doped with magnesium (Mg
    MeSH term(s) Tissue Engineering ; Bone and Bones ; Osteoblasts ; Apatites ; Bone Regeneration
    Chemical Substances Apatites
    Language English
    Publishing date 2023-09-16
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-023-42271-2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Energetic characterization of uracil derivatives: Orotic and isoorotic acids

    Amaral, Luísa M.P.F / Szterner, Piotr / Morais, Victor M.F / Ribeiro da Silva, Maria D.M.C / Ribeiro da Silva, Manuel A.V

    Thermochimica acta. 2020 Jan., v. 683

    2020  

    Abstract: The standard (po =0.1 MPa) molar enthalpies of formation of orotic and isoorotic acids, in the crystalline phase, were derived from the respective standard massic energies of combustion measured by static bomb combustion calorimetry, in oxygen, at T =298. ...

    Abstract The standard (po =0.1 MPa) molar enthalpies of formation of orotic and isoorotic acids, in the crystalline phase, were derived from the respective standard massic energies of combustion measured by static bomb combustion calorimetry, in oxygen, at T =298.15 K, as ‒821.7 ± 1.1 kJ mol−1 and ‒838.3 ± 1.9 kJ mol−1, respectively.The molecular structure and conformational behaviour of orotic and isoorotic acids were studied by theoretical calculations and the standard gas-phase molar enthalpies of formation were derived using an appropriate set of working reactions.Sublimation enthalpies, at the reference temperature T = 298.15 K, were estimated from difference between crystalline and gaseous enthalpies of formation and from statistically-based interaction indices derived from molecular surface electrostatic potentials.
    Keywords calorimetry ; chemical structure ; combustion ; electrostatic interactions ; enthalpy ; gases ; oxygen ; temperature ; uracil derivatives
    Language English
    Dates of publication 2020-01
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1500974-9
    ISSN 0040-6031
    ISSN 0040-6031
    DOI 10.1016/j.tca.2019.178474
    Database NAL-Catalogue (AGRICOLA)

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  4. Article ; Online: Effects of Sterilization and Hydrolytic Degradation on the Structure, Morphology and Compressive Strength of Polylactide-Hydroxyapatite Composites.

    Kasprzak, Mirosław / Szabłowska, Agnieszka / Kurzyk, Agata / Tymowicz-Grzyb, Paulina / Najmrodzki, Adrian / Woźniak, Anna / Antosik, Agnieszka / Pagacz, Joanna / Szterner, Piotr / Plichta, Andrzej / Wieciński, Piotr / Rusek-Wala, Paulina / Krupa, Agnieszka / Płociński, Przemysław / Rudnicka, Karolina / Biernat, Monika

    International journal of molecular sciences

    2022  Volume 23, Issue 18

    Abstract: Composites based on polylactide (PLA) and hydroxyapatite (HA) were prepared using a thermally induced phase separation method. In the experimental design, the PLA with low weight-average molar mass ( ...

    Abstract Composites based on polylactide (PLA) and hydroxyapatite (HA) were prepared using a thermally induced phase separation method. In the experimental design, the PLA with low weight-average molar mass (
    MeSH term(s) Animals ; Biocompatible Materials/chemistry ; Compressive Strength ; Durapatite/chemistry ; Humans ; Materials Testing ; Mice ; Polyesters/chemistry ; Polymers/chemistry ; Sterilization
    Chemical Substances Biocompatible Materials ; Polyesters ; Polymers ; poly(lactide) (459TN2L5F5) ; Durapatite (91D9GV0Z28)
    Language English
    Publishing date 2022-09-09
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2019364-6
    ISSN 1422-0067 ; 1422-0067 ; 1661-6596
    ISSN (online) 1422-0067
    ISSN 1422-0067 ; 1661-6596
    DOI 10.3390/ijms231810454
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: 5-Isopropylbarbituric and 2-thiobarbituric acids: An experimental and computational study

    Szterner, Piotr / Luísa M.P.F. Amaral / Manuel A.V. Ribeiro da Silva / Maria D.M.C. Ribeiro da Silva / Tiago L.P. Galvão

    Thermochimica acta. 2016 Feb. 10, v. 625

    2016  

    Abstract: The standard (po=0.1MPa) molar energies of combustion, ΔcUmo, for the crystalline 5-isopropylbarbituric and 2-thiobarbituric acids were determined, at the temperature of 298.15K, by static bomb or rotating bomb combustion calorimetry, respectively. For 5- ...

    Abstract The standard (po=0.1MPa) molar energies of combustion, ΔcUmo, for the crystalline 5-isopropylbarbituric and 2-thiobarbituric acids were determined, at the temperature of 298.15K, by static bomb or rotating bomb combustion calorimetry, respectively. For 5-isopropylbarbituric acid, the standard molar enthalpy of sublimation, ΔcrgHmo, at T=298.15K, was derived by Calvet microcalorimetry. The standard molar enthalpy of sublimation, at T=298.15K, was derived by the Clausius–Clapeyron equation, from the temperature-vapor pressure dependence, measured by the Knudsen mass-loss effusion method. These experiments allowed the determination of the standard molar enthalpy of formation, in the gaseous phase, at T=298.15K for 5-isopropylbarbituric acid. For 2-thiobarbituric acid, the gas-phase enthalpy of formation was calculated combining the result derived for the crystalline phase with literature data for the enthalpy of sublimation, at T=298.15K.These values were compared with estimates obtained from very accurate computational calculations using the G3 and G4 level theory composite methods.
    Keywords calorimetry ; combustion ; enthalpy ; equations ; gases ; sublimation ; temperature ; thiobarbituric acid
    Language English
    Dates of publication 2016-0210
    Size p. 36-46.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1500974-9
    ISSN 0040-6031
    ISSN 0040-6031
    DOI 10.1016/j.tca.2015.12.007
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  6. Article ; Online: Thermodynamic and structural study of tolfenamic acid polymorphs.

    Surov, Artem O / Szterner, Piotr / Zielenkiewicz, Wojciech / Perlovich, German L

    Journal of pharmaceutical and biomedical analysis

    2009  Volume 50, Issue 5, Page(s) 831–840

    Abstract: The article deals with the study of two polymorphic modifications in the space groups P2(1)/c (white form) and P2(1)/n (yellow form) of the tolfenamic acid. It also describes how the white form vapor pressure temperature dependence was determined by ... ...

    Abstract The article deals with the study of two polymorphic modifications in the space groups P2(1)/c (white form) and P2(1)/n (yellow form) of the tolfenamic acid. It also describes how the white form vapor pressure temperature dependence was determined by using the transpiration method and how thermodynamic parameters of the sublimation process were calculated. We have estimated the difference between the crystal lattice energies of the two polymorphic forms by solution calorimetry and found that the crystal lattice energy of the yellow form is 6.7+/-1.2 kJ mol(-1) higher than that of the white form, whereas Gibbs free energies of the forms obtained from the vapor pressure temperature dependence are practically the same. The modifications under consideration are monotropically related. From the practical point of view, the white form is more preferable due to its lower crystal lattice energy and better performing procedure. We have also studied the solubility, solvation and transfer processes of the tolfenamic acid white form in buffers (with various values of pH and ionic strengths), n-hexane and n-octanol. The thermodynamic parameters of the investigated processes have been discussed and compared with those determined for others fenamates. In the study we estimated specific and non-specific contributions of the solvation enthalpic term of the fenamate molecules with the solvents as well. The driving forces of the transfer processes from the buffers with pH 7.4 and different ionic strengths to n-octanol were analyzed. It was found that the relationship between the enthalpic and entropic terms depends essentially on the ionic strength. For the considered fenamates the transfer processes of the neutral molecules and the ionic forms are enthalpy-determined, whereas for the niflumic acid this process is entropy-determined.
    MeSH term(s) Buffers ; Calorimetry, Differential Scanning ; Flufenamic Acid/chemistry ; Hydrogen Bonding ; Hydrogen-Ion Concentration ; Ions ; Models, Chemical ; Niflumic Acid/chemistry ; Pressure ; Solubility ; Solutions ; Solvents/chemistry ; Temperature ; Thermodynamics ; ortho-Aminobenzoates/analysis ; ortho-Aminobenzoates/chemistry
    Chemical Substances Buffers ; Ions ; Solutions ; Solvents ; ortho-Aminobenzoates ; tolfenamic acid (3G943U18KM) ; Niflumic Acid (4U5MP5IUD8) ; Flufenamic Acid (60GCX7Y6BH)
    Language English
    Publishing date 2009-12-05
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 604917-5
    ISSN 1873-264X ; 0731-7085
    ISSN (online) 1873-264X
    ISSN 0731-7085
    DOI 10.1016/j.jpba.2009.06.045
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  7. Article: Thermochemistry of 6-propyl-2-thiouracil: An experimental and computational study

    Szterner, Piotr / Luísa M.P.F. Amaral / Manuel A.V. Ribeiro da Silva / Maria D.M.C. Ribeiro da Silva / Tiago L.P. Galvão

    Thermochimica acta. 2014 July 20, v. 588

    2014  

    Abstract: The standard (po=0.1MPa) molar enthalpy of formation of 6-propyl-2-thiouracil was derived from its standard molar energy of combustion, in oxygen, to yield CO2 (g), N2 (g) and H2SO4·115H2O (l), at T=298.15K, measured by rotating bomb combustion ... ...

    Abstract The standard (po=0.1MPa) molar enthalpy of formation of 6-propyl-2-thiouracil was derived from its standard molar energy of combustion, in oxygen, to yield CO2 (g), N2 (g) and H2SO4·115H2O (l), at T=298.15K, measured by rotating bomb combustion calorimetry. The vapor pressures as function of temperature were measured by the Knudsen effusion technique and the standard molar enthalpy of sublimation, ΔcrgHmo, at T=298.15K, was derived by the Clausius–Clapeyron equation. These two thermodynamic parameters yielded the standard molar enthalpy of formation, in the gaseous phase, at T=298.15K: −(142.5±1.9)kJmol−1. This value was compared with estimates obtained from very accurate computational calculations using the G3 and G4 composite methods.
    Keywords calorimetry ; carbon dioxide ; combustion ; energy ; enthalpy ; equations ; oxygen ; propylthiouracil ; sublimation ; sulfuric acid ; temperature
    Language English
    Dates of publication 2014-0720
    Size p. 68-74.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1500974-9
    ISSN 0040-6031
    ISSN 0040-6031
    DOI 10.1016/j.tca.2014.04.018
    Database NAL-Catalogue (AGRICOLA)

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