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1.
Dalton Trans ; 2020 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-32578638

RESUMO

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.

2.
Sci Rep ; 9(1): 10417, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31320659

RESUMO

We studied magnetostatic response of the Bi0.9La0.1FeO3- KBr composites (BLFO-KBr) consisting of nanosized (≈100 nm) ferrite Bi0.9La0.1FeO3 (BLFO) conjugated with fine grinded ionic conducting KBr. When the fraction of KBr is rather small (less than 15 wt%) the magnetic response of the composite is very weak and similar to that observed for the BLFO (pure KBr matrix without Bi1-xLaxFeO3 has no magnetic response as anticipated). However, when the fraction of KBr increases above 15%, the magnetic response of the composite changes substantially and the field dependence of magnetization reveals ferromagnetic-like hysteresis loop with a remanent magnetization about 0.14 emu/g and coercive field about 1.8 Tesla (at room temperature). Nothing similar to the ferromagnetic-like hysteresis loop can be observed in Bi1-zLazFeO3 ceramics with z ≤ 0.15, which magnetization quasi-linearly increases with magnetic field. Different physical mechanisms were considered to explain the unusual experimental results for BLFO-KBr nanocomposites, but only those among them, which are highly sensitive to the interaction of antiferromagnetic Bi0.9La0.1FeO3 with ionic conductor KBr, can be relevant.

3.
Biomed Res Int ; 2018: 2758347, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30402466

RESUMO

Stainless steel 316L is a material commonly used in cardiovascular medicine. Despite the various methods applied in stent production, the rates of in-stent restenosis and thrombosis remain high. In this study graphene was used to coat the surface of 316L substrate for enhanced bio- and hemocompatibility of the substrate. The presence of graphene layers applied to the substrate was investigated using cutting-edge imaging technology: energy-filtered low-voltage FE-SEM approach, scanning electron microscopy (SEM), Raman spectroscopy, and atomic force microscopy (AFM). The potential of G-316L surface to influence endothelial cells phenotype and endothelial-to-mesenchymal transition (EndoMT) has been determined. Our results show that the bio- and hemocompatible properties of graphene coatings along with known radial force of 316L make G-316L a promising candidate for intracoronary implants.


Assuntos
Materiais Revestidos Biocompatíveis/química , Células Endoteliais/metabolismo , Teste de Materiais , Stents , Humanos , Propriedades de Superfície
4.
Small ; 13(47)2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29116668

RESUMO

At the core of luminescence color and lifetime tuning of rare earth doped upconverting nanoparticles (UCNPs), is the understanding of the impact of the particle architecture for commonly used sensitizer (S) and activator (A) ions. In this respect, a series of core@shell NaYF4 UCNPs doped with Yb3+ and Ho3+ ions are presented here, where the same dopant concentrations are distributed in different particle architectures following the scheme: YbHo core and YbHo@…, …@YbHo, Yb@Ho, Ho@Yb, YbHo@Yb, and Yb@YbHo core-shell NPs. As revealed by quantitative steady-state and time-resolved luminescence studies, the relative spatial distribution of the A and S ions in the UCNPs and their protection from surface quenching has a critical impact on their luminescence characteristics. Although the increased amount of Yb3+ ions boosts UCNP performance by amplifying the absorption, the Yb3+ ions can also efficiently dissipate the energy stored in the material through energy migration to the surface, thereby reducing the overall energy transfer efficiency to the activator ions. The results provide yet another proof that UC phosphor chemistry combined with materials engineering through intentional core@shell structures may help to fine-tune the luminescence features of UCNPs for their specific future applications in biosensing, bioimaging, photovoltaics, and display technologies.

5.
Sci Rep ; 7: 41281, 2017 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-28112254

RESUMO

Laser induced white light emission was observed from porous graphene foam irradiated with a focused continuous wave beam of the infrared laser diode. It was found that the intensity of the emission increases exponentially with increasing laser power density, having a saturation level at ca. 1.5 W and being characterized by stable emission conditions. It was also observed that the white light emission is spatially confined to the focal point dimensions of the illuminating laser light. Several other features of the laser induced white light emission were also discussed. It was observed that the white light emission is highly dependent on the electric field intensity, allowing one to modulate the emission intensity. The electric field intensity ca. 0.5 V/µm was able to decrease the white light intensity by half. Origins of the laser-induced white light emission along with its characteristic features were discussed in terms of avalanche multiphoton ionization, inter-valence charge transfer and possible plasma build-up processes. It is shown that the laser-induced white light emission may be well utilized in new types of white light sources.

6.
Adv Colloid Interface Sci ; 236: 101-12, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27569200

RESUMO

Graphene-based materials have become very popular bionanotechnological instruments in the last few years. Since 2010, the graphene family materials have been recognized as worthy of attention due to its antimicrobial properties. Functionalization of graphene (or rather graphene oxide) surface creates the possibilities to obtain efficient antimicrobial agents. In this review, progress and advances in this field in the last few years are described and discussed. Special attention is devoted to materials based on graphene oxide in which specifically selected components significantly modify biological activity of this carbon structure. Short introduction concerns the physicochemical properties of the graphene family materials. In the section on antimicrobial properties, proposed mechanisms of activity against microorganisms are given showing enhanced action of nanocomposites also under light irradiation (photoinduced activity). Another important feature, i.e. toxicity against eukaryotic cells, is presented with up-to-date data. Taking into account all the information on the properties of the described materials and usefulness of the graphene family as antimicrobial agents, hopes and fears concerning their application are discussed. Finally, some examples of promising usage in medicine and other fields, e.g. in phytobiology and water remediation, are shown.


Assuntos
Anti-Infecciosos/farmacologia , Técnicas Biossensoriais , Bactérias Gram-Positivas/efeitos dos fármacos , Grafite/farmacologia , Nanocompostos/química , Anti-Infecciosos/química , Aspergillus/efeitos dos fármacos , Aspergillus/crescimento & desenvolvimento , Candida/efeitos dos fármacos , Candida/crescimento & desenvolvimento , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Positivas/crescimento & desenvolvimento , Grafite/química , Luz , Nanocompostos/efeitos da radiação , Nanocompostos/ultraestrutura , Óxidos , Purificação da Água/métodos
7.
Phys Chem Chem Phys ; 17(26): 17246-52, 2015 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-26073169

RESUMO

Optically stimulated persistent luminescence was investigated for europium-doped LaAlO3 nanocrystals. This system shows conventional luminescence of both the Eu(3+) line emission and the weak broad-band emission of Eu(2+) upon UV excitation. The persistent luminescence is predominantly associated with the Eu(3+) emission, and can be amplified significantly through irradiation with IR at 975 nm. The conventional luminescence from Eu(3+) is strongly enhanced when the material is excited simultaneously with both UV and IR radiation. The enhancement of persistent luminescence is accompanied by increased persistent photoconductivity. The charge transfer band of the LaAlO3:Eu(3+) nanocrystals in the UV excitation spectra significantly weakens with increasing IR excitation power, also correlating well with the enhancement of persistent luminescence. Finally, a mechanism is presented for the optically stimulated and persistent luminescence in this Eu(2+)- and Eu(3+)-doped LaAlO3 material.

8.
J Nanopart Res ; 16(11): 2690, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25346614

RESUMO

The synthesis, morphological characterization, and optical properties of colloidal, Eu(III) doped Gd2O3 nanoparticles with different sizes and shapes are presented. Utilizing wet chemical techniques and various synthesis routes, we were able to obtain spherical, nanodisk, nanotripod, and nanotriangle-like morphology of Gd2O3:Eu3+ nanoparticles. Various concentrations of Eu3+ ions in the crystal matrix of the nanoparticles were tested in order to establish the levels at which the concentration quenching effect is negligible. Based on the luminescence spectra, luminescence lifetimes and optical parameters, which were calculated using the simplified Judd-Ofelt theory, correlations between the Gd2O3 nanoparticles morphology and Eu3+ ions luminescence were established, and allowed to predict the theoretical maximum quantum efficiency to reach from 61 to 98 %. We have also discussed the impact of the crystal structure of Gd2O3 nanoparticles, as well as coordinating environment of luminescent ions located at the surface, on the emission spectra. With the use of a tunable femtosecond laser system and the Z-scan measurement technique, the values of the effective two-photon absorption cross-section in the wavelength range from 550 to 1,200 nm were also calculated. The nonlinear optical measurements revealed maximum multi-photon absorption in the wavelength range from 600 to 750 nm.

9.
Dalton Trans ; 43(21): 7752-9, 2014 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-24699861

RESUMO

Magnesium spinel (MgAl2O4) powders doped with Yb(3+) ions have been synthesized by a sol-gel method and heat-treated in the range of 700-1000 °C for 3 h. XRD patterns indicated that the powders have a cubic structure with high crystallite dispersion. Nanoparticles in the range of 10-30 nm are obtained as a function of the dopant concentration and sintering temperature. The main Yb(3+) zero-phonon line is located at 976 nm. The spectroscopic properties of the Yb(3+) ions are characterized by broad absorption spectroscopy and emission spectroscopy. Even at low temperature, the spectra reveal a strong distorted spinel lattice due to the high inversion rate between Mg(2+) tetrahedral sites and Al(3+) octahedral sites. The substitution of Mg(2+) ions by Yb(3+) ions favors the creation of Yb(3+) ion pairs which are observed in the cooperative luminescence spectra at around 500 nm. The luminescence decays are influenced by both the Yb(3+) content, the energy transfer between ions and by the presence of pairs and aggregates. Detailed analysis of the observed structural and spectroscopic measurements has been described in this manuscript.

10.
J Nanopart Res ; 16: 2176, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24453571

RESUMO

The synthesis of nanosized phosphors by using the non-thermal plasma-driven method is presented. The method allows to control the average grain size of nanocrystals. The synthesis of Eu3+-doped Y2O3 nanocrystalline phosphors at water solution of nitrates is described. The average sizes of nanocrystals were controlled by sintering temperature. Their structure, morphology, and luminescent properties were investigated.

11.
Nanoscale ; 6(3): 1855-64, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24356665

RESUMO

Lanthanide doped, up-converting nanoparticles have found considerable interest as luminescent probes in the field of bio-detection. Although the nanoparticles (NPs) have already been successfully applied for fluorescent bio-imaging and bio-assays, the efficiency of the up-conversion process seems to be the bottle-neck in rigorous applications. In this work, we have shown enhancement of the up-conversion in colloidal α-NaYF4:Yb(3+), Tb(3+) doped nanocrystals owing to passivation of their surface. We have studied quantitatively the influence of the shell type (NaYF4 and CaF2), its thickness, as well as the shell deposition method (i.e. single thick shell vs. multi-layer shell) on the luminescent properties of the nanoparticles. The results showed that up to 40-fold up-conversion intensity enhancement may be obtained for the core-shell nanoparticles in comparison with the bare core nanoparticles, irrespective of the shell type and deposition method. Moreover, the suitability of the NaYF4:Yb(3+), Tb(3+) core-shell NPs for multi-color emission and spectral multiplexing has been presented.


Assuntos
Coloides/química , Elementos da Série dos Lantanídeos/química , Nanopartículas/química , Bioensaio , Fluoreto de Cálcio/química , Transferência de Energia , Fluoretos/química , Ligantes , Luminescência , Microscopia Eletrônica de Transmissão , Nanotecnologia/métodos , Óptica e Fotônica , Solventes , Ácido Trifluoracético/química , Difração de Raios X , Ítrio/química
12.
J Nanopart Res ; 15(6): 1707, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23807867

RESUMO

Pure cubic phase ultra-small α-NaYF4:4 % Eu3+ colloidal nanoparticles were synthesized by thermal decomposition reaction using three various capping ligands, i.e., oleic acid, trioctylphosphine oxide, and hexadecylamine. To expose as many Eu3+ ions as possible to interactions with the surface-bounded ligands, the nanoparticles were fabricated to have the diameters below 10 nm. The geometrical structure and properties of surface ligands needed for qualitative estimation of their influence on spectroscopic features of the investigated Eu3+ doped nanoparticles were obtained from DFT quantum-chemical calculations. Significant changes of luminescence spectra shapes and luminescence lifetime values were observed upon changes in the local chemical environment. We show that the ratio R = 5D0 â†’ 7F1/5D0 â†’ 7F2 of the intensities of the forced electric dipole (J = 2) and magnetic dipole (J = 1) transitions in the synthesized Eu3+ doped nanoparticles is highly sensitive to the type of ligand present on the nanoparticle surface. Similarly, 5D0 luminescence lifetimes are found to be sensitive to the refractive index, and also to the dielectric constant of ligands used during the synthesis to coat nanoparticles surface. We argue that the photophysical and electro-optical properties of colloidal Eu3+ doped inorganic nanoparticles show hyper-sensitive response to the chemical surroundings in the close vicinity of the nanoparticle itself. The behavior of both steady-state luminescence and its kinetics demonstrates the potential suitability of the studied nanoparticles for constructing self-referencing optical nano-sensors.

13.
Polim Med ; 43(3): 129-34, 2013.
Artigo em Polonês | MEDLINE | ID: mdl-24377177

RESUMO

BACKGROUND: Researches have been synthesizing nanocomposites with antibacterial properties for a dozen of years. A lot of study have confirmed a high antibacterial activity of silver nanoparticles and oxygraphene. Silica, titanium dioxide and hydroxyapatites of 1-100 nm are used as carrier for these composites. OBJECTIVES: To synthesise graphene-silver nanocomposites and to determine their antibacterial properties. MATERIALS AND METHODS: The following bacteria strains from the American Type Culture Collection were tested: Staphylococcus aureus ATCC 6538 (Gram-positive bacteria), Escherichia coli ATCC 11229 (Gram-negative bacteria), Klebsiella pneumoniae ATCC 4352 (Gram-negative bacteria). Clinical isolates of bacteria strains (from wounds) were also tested (from species of Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae). The antibacterial effect of nanocomposites was determined by minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values according to the reference methods of Clinical and Laboratory Standards Institute (CLSI) for the determination of MICs of aerobic bacteria by broth microdilution. The samples have physical and chemical characteristics. RESULTS: The results showed bacteriostatic (0.4-1.6 microg/ml) and bactericidal (0.4-3.2 microg/ml) efficacy of composities. CONCLUSION: The synthesized nanocomposites of graphene-oxide can be used in biology and medicine as bacteriostatic and bactericidal factor and may be used as an alternative to antibiotics and chemioterapeutics.


Assuntos
Antibacterianos/síntese química , Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Grafite/farmacologia , Nanocompostos/química , Prata/farmacologia , Escherichia coli/efeitos dos fármacos , Grafite/química , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Nanopartículas , Prata/química , Staphylococcus aureus/efeitos dos fármacos
14.
Nanoscale ; 4(22): 6959-61, 2012 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-23072978

RESUMO

We report that non-contact optical temperature sensing can be achieved with the use of heavily Nd(3+) doped NaYF(4) nanoparticles. The temperature evaluation can be realized either by monitoring the absolute luminescence intensity or by measuring the intensity ratio of the two Stark components of the (4)F(3/2) multiplet in the Nd(3+) ions.

15.
J Biomed Nanotechnol ; 8(4): 605-12, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22852470

RESUMO

Hydroxyapatites (Ca10(PO4)6(OH)2 and Eu3+:Ca10(PO4)6(OH)2) were synthesized by aqueous synthesis route. Hydroxyapatites were impregnated with silver ions that were subsequently reduced. XRD, TEM, and SAED measurements were used in order to determine the crystal structure and morphology of the final products. The results showed the well crystallized hydroxyapatite grains with diameter of about 35 nm and with silver nanoparticles on their surface. The antimicrobial activity of the nanoparticles against: Staphylococcus aureus ATCC 6538 as model of the Gram-positive bacteria, Escherichia coli ATCC 11229, and Klebsiella pneumoniae ATCC 4352 as model of Gram-negative bacteria, were shown with the best activity against K. pneumoniae. These nanocomposite powders can be a promising antimicrobial agent and a fluorescent material for biodetection due to their optical and bioactive properties.


Assuntos
Antibacterianos/farmacologia , Európio/química , Hidroxiapatitas/química , Nanopartículas Metálicas/química , Nanocompostos/química , Prata/química , Prata/farmacologia , Antibacterianos/administração & dosagem , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Escherichia coli/efeitos dos fármacos , Európio/administração & dosagem , Hidroxiapatitas/administração & dosagem , Íons/química , Klebsiella pneumoniae/efeitos dos fármacos , Luminescência , Nanopartículas Metálicas/administração & dosagem , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Nanocompostos/administração & dosagem , Nanocompostos/ultraestrutura , Prata/administração & dosagem , Staphylococcus aureus/efeitos dos fármacos , Difração de Raios X
16.
Inorg Chem ; 49(6): 2684-91, 2010 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-20141181

RESUMO

Nanoparticles of a Nd-doped LaAlO(3) perovskite can be obtained rapidly and with quantitative yield using the Bradley (ether elimination) treatment of a mixture of individual Ln(2)Al(2)(O(i)Pr)(12)((i)PrOH)(2), Ln = La, Nd, in acetophenone. The initially produced particles are poorly crystalline, but their crystallinity improves strongly on heating to 800 degrees C, which leads also to a controllable aggregation. The prepared nanoparticles are rather solution stable and can easily be surface-modified, which opens prospects for their use as phosphors in bioimaging applications. The precursors, bimetallic isopropoxides of rare earth elements and aluminum with a 1:1 composition, Ln(2)Al(2)(O(i)Pr)(12)((i)PrOH)(2), can be prepared with high yields via direct dissolution of metallic lanthanoids in a solution of aluminum isopropoxide in a toluene-isopropanol medium or through a short time reflux of "Ln(O(i)Pr)(3)" with 1 equiv of Al(O(i)Pr)(3) in toluene. In spite of good volatility and their proper composition, the Ln(2)Al(2)(O(i)Pr)(12)((i)PrOH)(2), Ln = La, Nd, do not act as single-source precursors in MOCVD, because of their quantitative transformation into LnAl(3)(O(i)Pr)(12) together with Ln(5)O(O(i)Pr)(13) on evaporation. These molecules are, however, present intact in solution according to variable temperature NMR studies, which permits application of them successfully as single source precursors in the synthesis of Ln:LaAlO(3) perovskite nanopowders with compositions thoroughly controlled through the conditions of the synthesis. Luminescent properties of the Nd:LaAlO(3) were examined and discussed in detail. The thermal population of the (4)F(5/2) and (2)H(9/2) states was found as a consequence of the grain size effect causing difficulties in heat dissipation. Moreover, luminescence behavior of the powder annealed at a lowest temperature shows well-defined short-range order.


Assuntos
Óxido de Alumínio/química , Elementos da Série dos Lantanídeos/química , Neodímio/química , Cristalização , Cristalografia por Raios X , Luminescência , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Transmissão , Espectrometria de Massas por Ionização por Electrospray , Temperatura
17.
Chemistry ; 15(28): 6820-6, 2009 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-19544508

RESUMO

Investigation of the solvent and alkoxide precursor effect on the nonhydrolytic sol-gel synthesis of oxide nanoparticles by means of an ether elimination (Bradley) reaction indicates that the best crystallinity of the resulting oxide particles is achieved on application of aprotic ketone solvents, such as acetophenone, and of smallest possible alkoxide groups. The size of the produced primary particles is always about 5 nm caused by intrinsic mechanisms of their formation. The produced particles, possessing the composition of natural highly insoluble minerals, are biocompatible. Optical characteristics of the perovskite complex oxide nanoparticles can easily be controlled through doping with rare earth cations; for example, by Eu(3+). They can be targeted through surface modification by anchoring the directing biomolecules through a phosphate or phosphonate moiety. Testing of the distribution of Eu-doped BaTiO(3) particles, modified with ethylphosphonic acid, demonstrates their facile uptake by the plants with active fluid transport, resulting finally in their enhanced concentration within the cell membranes.


Assuntos
Éteres/química , Nanopartículas/química , Óxidos/síntese química , Cristalização , Géis , Modelos Moleculares , Estrutura Molecular , Óxidos/química , Transição de Fase , Solventes , Propriedades de Superfície
18.
Dalton Trans ; (26): 3412-21, 2008 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-18580977

RESUMO

Systematic structural study of the molecules, resulting from microhydrolysis of heterometallic beta-diketonate alkoxides of barium and strontium (single-source precursors of perovskite oxide materials), demonstrates that the structures of these products result from a thermodynamically driven self-assembly of metal cations and ligands directed towards the most densely packed cores. The ratio between metal cations, and of the cations to bidentate heteroligands, is easily changed to enable the highest packing density. The key to the application of single-source precursors appears to be the use of stoichiometric or superstoichiometric water amounts together with solvents preventing diffusion of possible homometallic intermediates. Eu-doped BaTiO3 nanoparticles have been successfully obtained and characterized.


Assuntos
Compostos de Cálcio/síntese química , Metais/química , Modelos Moleculares , Nanopartículas/química , Óxidos/química , Compostos de Cálcio/química , Hidrólise , Óxidos/síntese química , Transição de Fase , Titânio/química
19.
Pol J Microbiol ; 54(4): 305-10, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16599302

RESUMO

Photodynamic inactivation (PDI) may be a very promising alternative method for the antimicrobial treatment of periodontitis. Several studies have demonstrated the sensitivity of subgingival flora to PDI using toluidine blue, methylene blue, and chlorin e6 derivatives. In the present study we report the activity of the Fotolon sensitizer, composed of chlorin e6 and polyvinylpyrrolidone (PVP), against anaerobic bacteria isolated from periodontal diseases. Over 99.9% reduction in colony forming units in 20 Gram-positive and 30 Gram-negative clinical anaerobic strains was obtained.


Assuntos
Bactérias Anaeróbias/efeitos dos fármacos , Doenças Periodontais/microbiologia , Fármacos Fotossensibilizantes/farmacologia , Porfirinas/farmacologia , Bactérias Anaeróbias/isolamento & purificação , Bactérias Anaeróbias Gram-Negativas/efeitos dos fármacos , Bactérias Anaeróbias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/isolamento & purificação , Humanos , Técnicas In Vitro , Doenças Periodontais/tratamento farmacológico , Fotoquimioterapia
20.
J Biomed Opt ; 9(5): 1013-7, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15447023

RESUMO

The goal of practical photodynamic therapy (PDT) dosimetry is to optimize the distribution of a light dose delivered to tissue by selecting the irradiation time and geometry to match the geometry and optical properties of the tumor and surrounding tissue. Homogeneous irradiation is among one of the sources of correct PDT dosimetry. The goal of this study is to model and predict the influence of the shape of a treated organ in need of light dose correction. Thus efficiency of light delivery to the tissue volume is defined and calculated with shape factors of the uterine cervix as parameters. Two cases (parallel and divergent beam) of enlightening configuration are investigated. The calculations presented extend PDT dosimetry with the influence of the shape of the uterine cervix on PDT necrosis depth. This allows for photodynamic excitation light dose correction for more reliable treatments.


Assuntos
Colo do Útero/fisiopatologia , Colo do Útero/efeitos da radiação , Modelos Biológicos , Fotoquimioterapia/métodos , Radiometria/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Terapia Assistida por Computador/métodos , Colo do Útero/patologia , Simulação por Computador , Relação Dose-Resposta à Radiação , Feminino , Humanos , Luz , Doses de Radiação , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/fisiopatologia
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