69 research outputs found

    In vitro and in vivo studies on biocompatibility of carbon fibres

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    In the present study we focused on the in vitro and in vivo evaluation of two types of carbon fibres (CFs): hydroxyapatite modified carbon fibres and porous carbon fibres. Porous CFs used as scaffold for tissues regeneration could simultaneously serve as a support for drug delivery or biologically active agents which would stimulate the tissue growth; while addition of nanohydroxyapatite to CFs precursor can modify their biological properties (such as bioactivity) without subsequent surface modifications, making the process cost and time effective. Presented results indicated that fibre modification with HAp promoted formation of apatite on the fibre surface during incubation in simulated body fluid. The materials biocompatibility was determined by culturing human osteoblast-like cells of the line MG 63 in contact with both types of CFs. Both tested materials gave good support to adhesion and growth of bone-derived cells. Materials were implanted into the skeletal rat muscle and a comparative analysis of tissue reaction to the presence of the two types of CFs was done. Activities of marker metabolic enzymes: cytochrome c oxidase (CCO) and acid phosphatase were examined to estimate the effect of implants on the metabolic state of surrounding tissues. Presented results evidence the biocompatibility of porous CFs and activity that stimulates the growth of connective tissues. In case of CFs modified with hydroxyapatite the time of inflammatory reaction was shorter than in case of traditional CFs

    Calcium orthophosphate-based biocomposites and hybrid biomaterials

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    Experimental Study of Iron Complexes Containing N,N'-Coordinated o-Diiminobenzosemiquinonate π Radicals

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    Pylek traw [Poaceae] w powietrzu Sosnowca w latach 1997-2006

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    The article presents the analysis results of the grass pollen seasons from 1997 to 2006 in Sosnowiec. The research was carried out by means of the volumetric method with the use of a Burkard device. The duration of the pollen seasons was determined by means of the 98% method. The influence of meteorological conditions on the starting date and duration of the grass pollen seasons has been estimated in the article. The beginning of the pollen seasons was recorded between 23 April and 23 May. It has been demonstrated that the average duration of the pollen season amounted to 138 days. The period of maximum concentrations was recorded in June and the first half of July. The highest daily concentration was found in 2000 (495 grains in m³) and the highest annual sums in 2002 and 2000. The daily concentration distribution curve has shown three peaks. The highest values were recorded from 7 am until 11 am, from 13 pm until 17 pm and from 19 pm until 21 pm. It has been found that there is a significant influence of weather conditions (temperature, precipitation and relative humidity) on the beginning and duration of the pollen seasons and the period of maximum concentrations.Praca przedstawia wyniki analizy sezonów pylenia traw w latach 1997-2006 w Sosnowcu. Badania prowadzono metodą wolumetryczną aparatem typu Burkard. Długość sezonów pyłkowych wyznaczono metodą 98%. W pracy oceniono wpływ warunków meteorologicznych na termin rozpoczęcia i długość sezonów pyłkowych traw. Początek sezonów pyłkowych rejestrowano między 23.04-23.05. Wykazano że średnia długość sezonu pyłkowego wynosiła 138 dni. Najwyższe stężenie dobowe stwierdzono w 2000 roku (495 ziarn w m³), najwyższe sumy roczne w 2002 i 2000 roku. Okres maksymalnych stężeń notowano w czerwcu i pierwszej połowie lipca. Badania rytmiki dobowej pyłku traw wykazały najwyższe wartości pomiędzy 7⁰⁰-11⁰⁰, 13⁰⁰-17⁰⁰ i 19⁰⁰-21⁰⁰

    Ragweed (Ambrosia) pollen in aeroplankton of Upper Silesia

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    The work contains the analysis of Ambrosia pollen producing seasons in the atmosphere of Upper Silesia in the years 1998 - 2004. The research was carried out applying a volumetric method (Burkard pollen sampler) in Sosnowiec and the gravimetric method, for comparative purposes, in Sosnowiec, Będzin, Czeladź and Katowice. The highest pollen concentration in the research years was found in Sosnowiec and in 1999 in Czeladź. The ambrosia pollen in aeroplankton was noticed in the first ten days of August until the middle of October. The maximum pollen concentrations were from 16 August to 21 September. The highest pollen concentration was found in 1999 and 2002 (222 and 127 grains per 1m3 per 24h) on September 4th, the lowest concentration in 2001. Two genera - Ambrosia artemisiifolia and A. psilostachya - can be found over an area of Upper Silesia. They constitute the main source of pollen in aeroplankton, but its transportation from distant areas cannot be excluded. The pollen of these plants can be transported by the wind from neighbouring countries (the Czech Republic, Slovakia, Ukraine, Hungary).Analizowano przebieg sezonów pyłkowych ambrozji w atmosferze Górnego Śląska w latach 1998-2004. Badania prowadzono metodą wolumetryczną (aparat Burkarda) w Sosnowcu i metodą grawimetryczną, w celach porównawczych w Sosnowcu, Będzinie, Czeladzi i Katowicach. Pyłek ambrozji notowano od pierwszej dekady sierpnia do połowy pażdziernika. Wysokie koncentracje pyłku utrzymywały się w okresie od 16 sierpnia do 21 września. Najwyższą zawartość pyłku w powietrzu w ciągu doby zanotowano w 1999 i 2002 roku (222 i 127 ziarn w 1 m3 na 24h) 4 września, najniższą w 2001 roku (18 ziarn w 1 m3 na 24h). W rejonie Górnego śląska notowana jest obecność dwóch gatunków ambrozji: Ambrosia artemisiifolia i A. psilostachya. To one stanowią główne żródło pyłku w aeroplanktonie, jednak nie można wykluczyć dalekiego transportu. Pyłek tych roślin może być przenoszony z krajów ościennych (Czech, Słowacji, Ukrainy, Węgier)

    Electronic Structures of Five‐Coordinate Complexes of Iron Containing Zero, One, or Two π‐Radical Ligands: A Broken‐Symmetry Density Functional Theoretical Study

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    The electronic structures of a series of five‐coordinate complexes of iron containing zero, one, or two bidentate, organic π‐radical ligands and a monodentate ligand (pyridine, iodide) have been studied by broken‐symmetry (BS) density functional theoretical (DFT) methods. By analyzing the set of corresponding orbitals5 (CO) a convenient division of the spin‐up and spin‐down orbitals into 1) essentially doubly‐occupied molecular orbitals (MO), 2) exactly singly‐occupied MOs, 3) spin‐coupled pairs, and 4) virtual orbitals can be achieved and a clear picture of the spin coupling between the ligands (non‐innocence vs. innocence) and the central metal ion (dN configuration) can be generated. We have identified three classes of complexes which all contain a ferric ion (d5) with an intrinsic intermediate spin (SFe= 3/2) that yield 1) an St=3/2 ground spin state if the two bidentate ligands are closed‐shell species (innocent ligands); 2) if one π‐radical ligand is present, an St=1 ground state is obtained through intramolecular antiferromagnetic coupling; 3) if two such radicals are present, an St=1/2 ground state is obtained. We show unambiguously for the first time that the pentane‐2,4‐dione‐bis(S‐alkylisothiosemicarbazonato) ligand can bind as π‐radical dianion (L.TSC)2− in [FeIII(L.TSC)I] (St=1) (6); the description as [FeIV(LTSC3−)I] is incorrect. Similarly, the diamagnetic monoanion in 14 must be described as [FeIII(CN)2(L.TSC)]− (St=0) with a low‐spin ferric ion (d5, SFe=1/2) coupled antiferromagnetically to a π‐radical ligand; [FeII(CN)2(LTSC−)]− is an incorrect description

    Ocena zagrożenia pyłkiem Ambrosia L. w skali regionalnej na przykładzie miasta Sosnowca (Wyżyna Śląska, Polska)

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    The investigation of Ambrosia pollen counts in the air of Sosnowiec was carried out from 1998 to 2010 by means of the volumetric method. The pollen season which was determined by means of the 98% method started at the end of July and the beginning of August and lasted until the end of October. The highest Ambrosia pollen count was recorded in 1999 (222 grains x m-3) and the lowest in 2001 (18 grains x m-3). It was stated that the daily count of pollen grains depended on the wind direction and maximum air temperature. The strongest correlations were found with maximum temperature and with a wind direction from the south east. A high negative correlation coefficient was found between the frequency of inflows of air masses from the west and the annual total of pollen grains and the value of the maximum daily count. The closest sites of Ambrosia L. are at a distance of 25–40 kilometres from the sampling point. Significant correlations with the frequency of inflow of air masses can support the conclusion that Ambrosia pollen grains recorded in Sosnowiec were most probably carried not only from local sources but also, at least in part, from distant places.Badania koncentracji pyłku Ambrosia w powietrzu Sosnowca prowadzono w latach 1998-2010 metodą wolumetryczną. Początek sezonu pyłkowego Ambrosia, wyznaczony metodą 98%, rozpoczynał się na przełomie lipca i sierpnia i trwał do końca października. Wysokie koncentracje pyłku notowano najczęściej w trzeciej dekadzie sierpnia lub w pierwszej połowie września. Najwyższe stężenie pyłku Ambrosia odnotowano w 1999 roku (222 ziarn x m-3), najniższe w 2001 roku (18 ziarn x m-3). Wykazano, iż stężenie dobowe ziarn pyłku zależało od kierunku wiatru i temperatury maksymalnej powietrza. Najsilniejszą korelację stwierdzono dla temperatury maksymalnej i dla kierunku wiatru z południowego wschodu. Znaleziono wysoki ujemny współczynnik korelacji między częstością napływu mas powietrza z zachodu a wartością sumy rocznej ziarn pyłku oraz z wartością maksymalnego stężenia. Stwierdzono również oddziaływanie masy powietrza polarno-morskiego na długość sezonów pyłkowych i na wartości maksymalnego stężenia Ambrosia. Przy napływie tego typu powietrza notowano dłuższe sezony pyłkowe oraz niższe maksima sezonowe. Stanowiska z Ambrosia zostały stwierdzone w odległości 25-40 km na SW i NW od punktu pomiarowego. Istotne korelacje z częstością napływu mas powietrza mogą potwierdzać fakt, iż ziarna pyłku Ambrosia rejestrowane w Sosnowcu pochodzą nie tylko z lokalnych źródeł ale również z dalekiego transportu

    Molecular and Electronic Structures of Tetrahedral Complexes of Nickel and Cobalt Containing N,N‘-Disubstituted, Bulky o-Diiminobenzosemiquinonate(1−) π-Radical Ligands

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    The reaction of 2 equiv of the bulky ligand N,N‘-bis(3,5-di-tert-butylphenyl)-1,2-phenylenediamine, H2[3LPDI], excess triethylamine, and 1 equiv of M(CH3CO2)2·4H2O (M = Ni, Co) in the presence of air in CH3CN/CH2Cl2 solution yields violet-black crystals of [NiII(3LISQ)2] CH3CN (1) or violet crystals of [Co(3L)2] (3). By using Pd(CH3CO2)2 as starting material, green-blue crystals of [PdII(3LISQ)2]·CH3CN (2) were obtained. Single-crystal X-ray crystallography revealed that 1 and 3 contain (pseudo)tetrahedral neutral molecules [M(3L)2] (M = Ni, Co) whereas in 2 nearly square planar, neutral molecules [PdII(3LISQ)2] are present. Temperature-dependent susceptibility measurements established that 1 and 2 are diamagnetic (S = 0) whereas 3 is paramagnetic with an S = 3/2 ground state. It is shown that 1 contains two π radical benzosemiquinonate(1−)-type monoanions, ((3LISQ)1-•, Srad = 1/2), and a central Ni(II) ion (d8; S = 1) which are antiferromagnetically coupled yielding the observed St = 0 ground state. This result has been confirmed by broken symmetry DFT calculations of 1. In contrast, the St = 3/2 ground state of 3 is more difficult to understand:  the two resonance structures [CoIII(3LISQ)(3LPDI)] ↔ [CoII(3LPDI)(3LIBQ)] might be invoked (for tetrahedral [CoII(3LISQ)2] containing an SCo = 3/2 with two antiferromagnetically coupled π-radical ligands an St = 1/2 is anticipated). Complex 2 is diamagnetic (S = 0) containing a PdII ion (d8, SPd = 0 in an almost square planar ligand field) and two antiferromagnetically coupled ligand radicals (Srad = 1/2). The electrochemistry and spectroelectrochemistry of 1,2, and 3 have been studied, and electron-transfer series comprising the species [M(L)2]z (z = 2+, 1+, 0, 1−, 2−) have been established. All oxidations and reductions are ligand centered

    Vibrational spectra of Ca(BH4)2

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    IR and Raman data were obtained from α-, β-, and mixed (β,γ)-Ca(BH 4) 2 samples and from the deuterated β,γ phase mixture. The results obtained with α phase indicate that the DFT calculated values for the B−H stretching modes and the lattice vibrations are fairly close to the experimental values. The spectral behavior at temperatures around the transition to the β phase shows a continuous transition and suggests the presence of disorder caused by reorientational motions of the [BH 4] − ion in the β phase. The data indicate that there are more deformation bands observed for the mixed (β,γ) samples than for the α phase which indicates structural variations between the β and the γ phases
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