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1.
Environ Int ; 126: 560-567, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30852443

RESUMO

Photocatalytic catalysis is widely used for pollutant degradation. Since some pollutants with oxidative nature are readily reduced rather than oxidized and reductive reaction caused by photogenerated electrons is limited in the presence of oxygen, photocatalytic reduction process is more applicable for the degradation of pollutants with oxidative nature than oxidation. In this work, a novel bio-photoelectric reductive degradation system (BPRDS), composed of an electrochemically active bacterium Shewanella oneidensis MR-1 and a visible-light photocatalyst Ag3PO4, was established under anaerobic conditions and its photodegradation performance was evaluated through degrading rhodamine B (RhB), a typical organic pollutant. The as-synthesized Ag3PO4 nanoparticles exhibited absorption in the entire visible spectral range of 400-800 nm. RhB could be degraded in BPRDS with visible light irradiation under anaerobic conditions, but not be decomposed in the absence of Shewanella cells. Block of Mtr respiratory pathway, a transmembrane electron transport chain, resulted in a reduction in degradation rate of RHB in BPRDS. Dose of riboflavin also substantially decreased the RhB degradation. These results suggest that the electrons released by Shewanella were involved in the RhB photodegradation, which was achieved via a stepwise N-deethylation process. In BPRDS, RhB was degraded by photoreduction, rather than photooxidation. This work is useful to develop integrated physico-chemical-microbial systems for pollutant degradation, facilitate better understanding about the biophotoelectric reductive degradation mechanisms and beneficial to their applications for environmental remediation.


Assuntos
Fosfatos/química , Rodaminas/metabolismo , Shewanella/metabolismo , Compostos de Prata/química , Catálise , Luz , Oxirredução , Fosfatos/efeitos da radiação , Fotólise , Compostos de Prata/efeitos da radiação
2.
Environ Sci Pollut Res Int ; 23(13): 13458-66, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27026549

RESUMO

Visible light-driven photocatalytic inactivation of Escherichia coli was performed using hydroxyapatite-supported Ag3PO4 nanocomposites (Ag3PO4/HA). The antibacterial performance was evaluated by the methods of zone of inhibition plates and minimum inhibitory concentration test. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to investigate the instability and transformation of the nanocomposite by comparing the crystalline, phase, and the morphology before and after exposure to Luria-Bertani culture medium under visible light irradiation. Ag3PO4 nanoparticles on the support were found to be shortly transformed into AgCl due to high chloride concentration of Luria-Bertani culture medium. The AgCl/HA nanocomposite showed both excellent intrinsic antibacterial performance contributed by the released silver ions and visible light-induced photocatalytic disinfection toward E. coli cells. This dual antibacterial function mechanism was validated by trapping the hydroxyl free radical and detecting the silver ions during the photocatalytic antibacterial process. The morphological change of E. coli cells in different reaction intervals was obtained by scanning electron microscopy (SEM) to complementally verify photocatalytic inactivation of E. coli. This work suggests that an essential comparison study is required for the antibacterial materials before and after the photocatalytic inactivation of bacterial cells using Ag3PO4 nanoparticles or Ag3PO4-related nanocomposites in mediums containing high-concentration chloride ions.


Assuntos
Antibacterianos/farmacologia , Cloretos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/efeitos da radiação , Luz , Fosfatos/farmacologia , Compostos de Prata/farmacologia , Antibacterianos/química , Antibacterianos/efeitos da radiação , Catálise , Cloretos/química , Cloretos/efeitos da radiação , Durapatita/química , Durapatita/farmacologia , Durapatita/efeitos da radiação , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/ultraestrutura , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanocompostos/química , Nanocompostos/efeitos da radiação , Fosfatos/química , Fosfatos/efeitos da radiação , Compostos de Prata/química , Compostos de Prata/efeitos da radiação , Difração de Raios X
3.
Water Res ; 81: 366-74, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26107659

RESUMO

As a high-quantum-efficiency photocatalyst, the serious photo-corrosion of silver phosphate (Ag3PO4), limits the practical applications in water purification and challenges us. Herein, Ag3PO4 is found to have a high stability under natural indoor weak light irradiation, suggesting that we can employ it by adopting a new application strategy. In our studies, rhodamine B (RhB, cationic dye), methyl orange (MO, anionic dye) and RhB-MO mixture aqueous solutions are used as the probing reaction for the degradation of organic wastewater. It is found that RhB, MO and RhB-MO can be completely degraded after 28 h under natural indoor weak light irradiation, indicating that multi-component organic contaminants can be efficiently degraded by Ag3PO4 under natural indoor weak light irradiation. The density of natural indoor weak light is measured to be 72cd, which is merely one-thousandth of 300 W xenon lamp (68.2 × 10(3)cd). Most importantly, Ag3PO4 shows a high stability under natural indoor weak light irradiation, demonstrated by the formation of fairly rare Ag. Furthermore, we also investigate the influence of inorganic ions on organic dyes degradation. It shows that the Cl(-) and Cr(6+) ions with high concentrations in wastewater have significantly decreased the degradation rate. From the viewpoint of energy saving and stability, this study shows us that we can utilize the Ag-containing photocatalysts under natural indoor weak light, which could be extended to indoor air cleaning process.


Assuntos
Luz , Fosfatos/efeitos da radiação , Compostos de Prata/efeitos da radiação , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/efeitos da radiação , Compostos Azo/química , Compostos Azo/efeitos da radiação , Catálise , Corantes/química , Corantes/efeitos da radiação , Cinética , Fosfatos/química , Rodaminas/química , Rodaminas/efeitos da radiação , Compostos de Prata/química , Poluentes Químicos da Água/química , Purificação da Água/métodos
4.
J Hazard Mater ; 293: 72-80, 2015 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-25827270

RESUMO

Since the photocatalytic capability is determined by the separation and transmission efficiency of photoinduced charges, its improvement remains a challenge for development of efficient photocatalysts. Here, we made large improvement on the surface of Ag3PO4 using Co(II)-grafted Ag3PO4 by a hydrothermal method. During the photocatalytic process, Co(II) was oxidized to Co(III) by the photogenerated holes under visible light radiation, which enhanced the separation efficiency of photogenerated charges. Meanwhile, the Co(III) as-formed could oxidize dye molecules, which recovered the Co(II). The synergy of Co(II) and Ag3PO4 greatly promoted the separation and transmission efficiency of the photogenerated charges, and severely improved the photocatalytic activity of Ag3PO4. The surface grafted Co(II) on Ag3PO4 is responsible for the enhancement of photocatalytic activity.


Assuntos
Cobalto/química , Cobalto/efeitos da radiação , Luz , Fosfatos/química , Fosfatos/efeitos da radiação , Compostos de Prata/química , Compostos de Prata/efeitos da radiação , Compostos Azo/química , Catálise , Corantes/química , Oxirredução
5.
Opt Express ; 22(23): 29020-30, 2014 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-25402141

RESUMO

The effects of γ-irradiation on potassium dihydrogen phosphate crystals containing arsenic impurities are investigated with different optical diagnostics, including UV-VIS absorption spectroscopy, photo-thermal common-path interferometer and photoluminescence spectroscopy. The optical absorption spectra indicate that a new broad absorption band near 260 nm appears after γ-irradiation. It is found that the intensity of absorption band increases with the increasing irradiation dose and arsenic impurity concentration. The simulation of radiation defects show that this absorption is assigned to the formation of AsO44⁻ centers due to arsenic ions substituting for phosphorus ions. Laser-induced damage threshold test is conducted by using 355 nm nanosecond laser pulses. The correlations between arsenic impurity concentration and laser induced damage threshold are presented. The results indicate that the damage performance of the material decreases with the increasing arsenic impurity concentration. Possible mechanisms of the irradiation-induced defects formation under γ-irradiation of KDP crystals are discussed.


Assuntos
Arsênico/análise , Vidro/química , Lasers , Óptica e Fotônica , Fosfatos/efeitos da radiação , Compostos de Potássio/efeitos da radiação , Arsênico/efeitos da radiação , Cristalização/métodos , Relação Dose-Resposta à Radiação , Desenho de Equipamento , Raios gama , Vidro/efeitos da radiação , Teste de Materiais , Fosfatos/análise , Compostos de Potássio/análise , Doses de Radiação , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier
6.
Luminescence ; 29(8): 1019-26, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24723439

RESUMO

Thermoluminescence (TL) materials are widely used in radiation measurements. The best-known applications of TL materials are in the dosimetry of ionizing radiation, and in CTV screen phosphors, scintillators, X-ray laser materials, etc. The TL glow curve and its kinetic parameters for annealed LaPO4 at different constant temperatures and for Dy(3+) -doped LaPO4 phosphors irradiated by gamma-rays are reported here. The samples were irradiated using a (60) Co gamma-ray source at a dose of 10 Gy and the heating rate used for TL measurements was 5 ºC/s. The samples were characterized using X-ray diffraction (XRD), Fourier transform infrared, transmission electron microscopy and TL techniques. The XRD pattern shows that the prepared phosphor has a good crystalline structure with an average crystallite size of ~ 18 nm. The samples show good TL peaks for 0.05, 0.1 and 0.2 mole % doping concentrations of Dy(3+) ions and anneal above 400 ºC. The TL glow curve characteristics of annealed LaPO4 and Dy(3+) -doped LaPO4 were analyzed and trapping parameters calculated using various methods. All TL glow curves obey the second-order kinetics with a single glow peak, which reveals that only one set of trapping parameter is set for a particular temperature. The TL sensitivity was found to depend upon the annealing temperature and Dy(3+) doping concentration. The prepared sample may be a new nano phosphor and be useful in TL dosimetry.


Assuntos
Medições Luminescentes/métodos , Fosfatos/química , Disprósio/química , Raios gama , Microscopia Eletrônica de Transmissão , Fosfatos/efeitos da radiação , Espectroscopia de Infravermelho com Transformada de Fourier , Dosimetria Termoluminescente , Difração de Raios X
7.
Opt Express ; 22(26): 32293-300, 2014 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-25607194

RESUMO

We demonstrate a simple, compact and cost-efficient diode laser pumped frequency doubling system at 795 nm in the low power regime. In two configurations, a bow-tie four-mirror ring enhancement cavity with a PPKTP crystal inside and a semi-monolithic PPKTP enhancement cavity, we obtain 397.5nm ultra-violet coherent radiation of 35mW and 47mW respectively with a mode-matched fundamental power of about 110mW, corresponding to a conversion efficiency of 32% and 41%. The low loss semi-monolithic cavity leads to the better results. The constructed ultra-violet coherent radiation has good power stability and beam quality, and the system has huge potential in quantum optics and cold atom physics.


Assuntos
Amplificadores Eletrônicos , Lasers de Estado Sólido , Fosfatos/química , Titânio/química , Cristalização , Transferência de Energia , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Fosfatos/efeitos da radiação , Titânio/efeitos da radiação , Raios Ultravioleta
8.
Chembiochem ; 14(17): 2277-83, 2013 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-24123793

RESUMO

We report the synthesis and photolytic properties of caged inorganic phosphates (Pi compounds) based on the 2-(4'-{bis[2-(2-methoxyethoxy)ethyl]amino}-4-nitro-[1,1'-biphenyl]-3-yl)propan-1-ol (EANBP) and 7-(diethylamino)coumarin-4-yl]methyl (DEACM) protecting groups. The EANBP-Pi showed unprecedented photolysis efficiency at 405 nm, with 95 % release of free phosphate and a quantum yield of 0.28. Thanks to the high two-photon sensitivity of the EANBP chromophore, Pi release through two-photon photolysis is also possible, with an action cross section of 20.5 GM at 800 nm. Two bioactivatable acetoxymethyl protection groups were added to the "caged-Pi" compounds. The resulting triesters of phosphoric acid were able to diffuse through the cellular membranes of plant cells. Once inside a cell, the cleavage of these biocleavable motifs by intracellular esterases allows intracellular accumulation of EANBP-Pi. Bis(AM)-EANBP-Pi therefore represents a very attractive tool for study of the Pi signal transduction cascade in living cells.


Assuntos
Permeabilidade da Membrana Celular , Luz , Fosfatos/química , Fosfatos/síntese química , Fotólise/efeitos da radiação , Fótons , Arabidopsis/química , Arabidopsis/citologia , Arabidopsis/crescimento & desenvolvimento , Sobrevivência Celular , Estrutura Molecular , Fosfatos/metabolismo , Fosfatos/efeitos da radiação , Raios Ultravioleta
9.
Opt Express ; 21(14): 16799-813, 2013 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-23938531

RESUMO

Micro-machining is the most promising method for KH(2)PO(4) crystal to mitigate the surface damage growth in high power laser system. In this work, spherical mitigation pit is fabricated by micro-milling with an efficient machining procedure. The light intensification caused by rear surface features before and after mitigation is numerically modeled based on the finite-difference time-domain method. The results indicate that the occurrence of total internal reflections should be responsible for the largest light intensification inside the crystal. For spherical pits after mitigation, the light intensification can be greatly alleviated by preventing the occurrence of total internal reflections. The light intensification caused by spherical mitigation pit is strongly dependent on the width-depth ratio and it is suggested that the width-depth ratio of spherical mitigation pit must be devised to be larger than 5.0 to achieve the minimal light intensification for the mitigation of surface damage growth. Laser damage tests for KH(2)PO(4) crystal validate that the laser damage resistance of initially damaged surface can be retrieved to near the level of ideal surface by replacing initial damage site with predesigned mitigation pit.


Assuntos
Lasers , Lentes , Modelos Químicos , Fosfatos/química , Fosfatos/efeitos da radiação , Compostos de Potássio/química , Compostos de Potássio/efeitos da radiação , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Espalhamento de Radiação
10.
Artigo em Inglês | MEDLINE | ID: mdl-23802163

RESUMO

The aim of this research was development of new system for the treatment of highly polluted wastewater (COD = 10240 mg/L; SS = 2860 mg/L) originating from vine-making industry. The system consisted of the main treatment that included electrochemical methods (electro oxidation, electrocoagulation using stainless steel, iron and aluminum electrode sets) with simultaneous sonication and recirculation in strong electromagnetic field. Ozonation combined with UV irradiation in the presence of added hydrogen peroxide was applied for the post-treatment of the effluent. Following the combined treatment, the final removal efficiencies of the parameters color, turbidity, suspended solids and phosphates were over 99%, Fe, Cu and ammonia approximately 98%, while the removal of COD and sulfates was 77% and 62%, respectively. A new approach combining electrochemical methods with ultrasound in the strong electromagnetic field resulted in significantly better removal efficiencies for majority of the measured parameters compared to the biological methods, advanced oxidation processes or electrocoagulation. Reduction of the treatment time represents another advantage of this new approach.


Assuntos
Peróxido de Hidrogênio/química , Ozônio/química , Raios Ultravioleta , Eliminação de Resíduos Líquidos/métodos , Poluentes da Água/química , Poluentes da Água/efeitos da radiação , Amônia/química , Amônia/efeitos da radiação , Análise da Demanda Biológica de Oxigênio , Cobre/química , Cobre/efeitos da radiação , Eletroquímica/métodos , Ferro/química , Ferro/efeitos da radiação , Nefelometria e Turbidimetria , Oxidantes/química , Oxirredução , Fosfatos/química , Fosfatos/efeitos da radiação , Sonicação , Sulfatos/química , Sulfatos/efeitos da radiação , Águas Residuárias , Vinho
11.
Opt Express ; 21(4): 4854-63, 2013 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-23482019

RESUMO

The self-focusing characteristic of 355 nm, 3.3 ns pulses propagating through phosphate glass samples is found to significantly change during repeated exposure. The results indicate this change is related to the formation of color centers in the material as well as the generation of a transient defect population during exposure to the laser pulses. A model is used to fit the experimental data and obtain an estimated range of values for the modified linear and nonlinear indices of refraction.


Assuntos
Vidro/química , Vidro/efeitos da radiação , Lasers , Lentes , Fosfatos/química , Fosfatos/efeitos da radiação , Teste de Materiais , Raios Ultravioleta
12.
Opt Express ; 21(2): 1395-403, 2013 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-23389121

RESUMO

We demonstrate that bulk Rb-doped KTiOPO4 (RKTP) shows improved susceptibility to gray-tracking compared to flux-grown KTiOPO4 . We show high-fidelity periodic poling of 1 mm thick RKTP with a period of 3.18 µm for second harmonic generation at 398 nm with a normalized conversion efficiency of 1.79%/Wcm. The crystal is used to frequency-double 138 fs-long pulses with an efficiency of 20% and a peak intensity of 560 MW/cm² without visible gray-tracking signs. We demonstrate that two-photon absorption is the predominant mechanism limiting the SHG efficiency in this spectral range at high peak powers and high repetition rates.


Assuntos
Lasers de Estado Sólido , Fosfatos/química , Fosfatos/efeitos da radiação , Rubídio/química , Rubídio/efeitos da radiação , Titânio/química , Titânio/efeitos da radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Teste de Materiais , Espalhamento de Radiação
13.
J Hazard Mater ; 244-245: 86-93, 2013 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-23246944

RESUMO

Ag(3)PO(4)/graphene-oxide (Ag(3)PO(4)/GO) composite has been synthesized by a liquid phase deposition method, and used for the photodegradation of organic dyes in water under visible light. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscope, N(2) sorption-desorption, and UV-vis diffuse reflectance spectra. The SEM image indicated that Ag(3)PO(4) particles were mainly distributed on the surface of GO sheets uniformly. DRS analysis revealed that the samples had good visible light response. The photocatalytic activity of Ag(3)PO(4)/GO composite was evaluated by decomposing of dyes (such as methyl orange, rhodamine B) in water under visible or UV-vis light irradiation. The degradation results indicated that the photocatalytic performance of Ag(3)PO(4)/GO was greatly enhanced due to the improved adsorption performance and separation efficiency of photo-generated carriers. The Ag(3)PO(4)/GO composite with GO content of 15 wt.% exhibited superior activity under visible light irradiation. After 50 min of reaction, the degradation ratio of MO was about 86.7%, while RhB solution could be completely degraded within 30 min of reaction. Further study proved that the direct oxidation of pollutants by holes has played a major role in the degradation process. The results of this work would provide a new sight for the construction of visible light-responsive photocatalysts with high performance.


Assuntos
Corantes/química , Grafite/química , Fosfatos/química , Compostos de Prata/química , Poluentes Químicos da Água/química , Catálise , Corantes/efeitos da radiação , Grafite/efeitos da radiação , Luz , Fosfatos/efeitos da radiação , Fotólise , Compostos de Prata/efeitos da radiação , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/efeitos da radiação , Difração de Raios X
14.
Opt Express ; 20(18): 20447-58, 2012 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-23037093

RESUMO

The transient changes in the optical properties of bulk DKDP material arising from its exposure to high temperatures and pressures associated with localized laser energy deposition are investigated. Two methods for initiation of laser-induced breakdown are used, intrinsic, involving relatively large energy deposition brought about by focusing of the laser beam to high intensities, and extrinsic, arising from more localized deposition due to the presence of pre-existing absorbing damage initiating defects. Each method leads to a very different volume of material being affected, which provides for different material thermal relaxation times to help better understand the processes involved.


Assuntos
Transferência de Energia , Lasers , Modelos Químicos , Fosfatos/química , Fosfatos/efeitos da radiação , Compostos de Potássio/química , Compostos de Potássio/efeitos da radiação , Absorção , Simulação por Computador , Cristalização , Doses de Radiação
15.
Radiat Prot Dosimetry ; 152(4): 463-7, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22611207

RESUMO

Dy(3+)-doped NaCaPO(4) phosphor was synthesised at an initiating combustion temperature of 600°C, using urea as the fuel. The crystallinity of the phosphor was investigated by using X-ray diffraction. The photoluminescence and thermoluminescence (TL) behaviours of NaCaPO(4):Dy(3+) phosphor was also studied. It has a simple TL glow curve structure, which does not change when exposed to gamma-rays. A TL glow peak is observed at 230°C and TL intensity is around 1.15 times more compared with commercial CaSO(4):Dy TLD phosphor. The TL characteristics of the phosphor prepared show that it has good sensitivity, linear response with gamma-rays exposure, emission in the blue-yellow regions of the spectrum, negligible fading and excellent reusability. These results make Dy(3+)-doped NaCaPO(4) phosphor attractive for TLD applications.


Assuntos
Fosfatos de Cálcio/química , Fosfatos de Cálcio/efeitos da radiação , Medições Luminescentes/métodos , Fosfatos/química , Fosfatos/efeitos da radiação , Dosimetria Termoluminescente/métodos , Relação Dose-Resposta à Radiação , Doses de Radiação
16.
Opt Express ; 19(9): 7929-36, 2011 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-21643042

RESUMO

We report the relationship between the initial glass composition and the resulting microstructural changes after direct femtosecond laser waveguide writing with a 1 kHz repetition rate Ti:sapphire laser system. A zinc polyphosphate glass composition with an oxygen to phosphorus ratio of 3.25 has demonstrated positive refractive index changes induced inside the focal volume of a focusing microscope objective for laser pulse energies that can achieve intensities above the modification threshold. The permanent photo-induced changes can be used for direct fabrication of optical waveguides using single scan writing techniques. Changes to the localized glass network structure that produce positive changes in the refractive index of zinc phosphate glasses upon femtosecond laser irradiation have been studied using scanning confocal micro-Raman and fluorescence spectroscopy.


Assuntos
Vidro/química , Vidro/efeitos da radiação , Lasers , Fosfatos/química , Fosfatos/efeitos da radiação , Espectrometria de Fluorescência/métodos , Análise Espectral Raman/métodos , Compostos de Zinco/química , Compostos de Zinco/efeitos da radiação , Teste de Materiais/métodos
17.
Vox Sang ; 101(1): 21-7, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21155835

RESUMO

BACKGROUND: The effect of gamma irradiation on leucoreduced red-blood-cells (RBCs) stored in an additive solution (AS) containing phosphate, adenine, glucose, guanosine, saline and mannitol (PAGGS-M) has not yet been studied, and there are different recommendations about storage time of leucoreduced RBCs after irradiation. STUDY DESIGN AND METHODS: We studied 63 leucoreduced RBC units. All RBCs were stored in AS PAGGS-M and leucoreduced on the collection day. Twenty-one components were irradiated on Day +14 with 30 Gy and 22 served as non-irradiated controls. Samples were drawn and analysed from these 43 units on Day +7, +14, +21, +28, +35, +42 and +49 from the collection day. From 20 units, no samples were taken earlier than on Day +49. Of these, 10 components had been irradiated on Day +14 with 30 Gy and 10 served as non-irradiated controls. RESULTS: Gamma irradiation induced an enhanced in vitro haemolysis rate in the irradiated components. One of the irradiated units showed a haemolysis rate over the recommended limit of 0·8% on Day +42 and four on Day +49. The leakage of potassium ions from irradiated RBCs started to increase faster than that of unirradiated RBCs from the day of irradiation. Lactate dehydrogenase levels increased faster in irradiated units 3 weeks after irradiation. We showed that taking samples weekly does not affect the final result. CONCLUSIONS: Our findings show that the European recommendations should not be changed in regard to the limitation of the storageability after irradiation of leucoreduced RBCs. The damage after irradiation and storage cannot be prevented by using the high-quality AS PAGGS-M.


Assuntos
Preservação de Sangue , Eritrócitos/metabolismo , Eritrócitos/efeitos da radiação , Raios gama , L-Lactato Desidrogenase/metabolismo , Potássio/metabolismo , 2,3-Difosfoglicerato/metabolismo , 2,3-Difosfoglicerato/efeitos da radiação , Adenina , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/efeitos da radiação , Contagem de Células Sanguíneas , Índices de Eritrócitos/efeitos da radiação , Glucose , Guanosina , Hemólise/efeitos da radiação , Humanos , Concentração de Íons de Hidrogênio/efeitos da radiação , L-Lactato Desidrogenase/efeitos da radiação , Manitol , Fosfatos/metabolismo , Fosfatos/efeitos da radiação , Potássio/efeitos da radiação
18.
Photochem Photobiol Sci ; 10(1): 123-7, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21063589

RESUMO

The irradiation of a series of phenyl sulfonates and phosphates leads to the quantitative release of acidity with a reasonable quantum yield (≈0.2). Products characterization, ion chromatography analysis and potentiometric titration are consistent with the intervening of two different paths in this reaction, viz. cationic with phosphates and (mainly) radical with sulfonates.


Assuntos
Sulfonatos de Arila/química , Cátions/química , Radicais Livres/química , Fosfatos/química , Ácidos/química , Sulfonatos de Arila/efeitos da radiação , Fosfatos/efeitos da radiação , Fotólise , Teoria Quântica
19.
Spectrochim Acta A Mol Biomol Spectrosc ; 77(3): 638-42, 2010 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-20674474

RESUMO

Polycrystalline Ca(7)Mg(2)P(6)O(24):Eu(2+),Mn(2+) phosphors were prepared by a solid-state reaction under a weak reductive atmosphere. The phosphors have been characterized by X-ray diffraction and fluorescence measurements. The results show that the obtained phosphors are of single-phase rhombohedral Ca(7)Mg(2)P(6)O(24). Upon excitation of 355nm ultraviolet (UV) light, two intense broad bands have clearly been observed due to the allowed 5d-4f transition of Eu(2+) and the forbidden (4)T(1)-(6)A(1) transition of Mn(2+), respectively. A white light has been obtained from Ca(7)Mg(2)P(6)O(24):0.035Eu(2+),0.5Mn(2+) phosphor with CIE chromaticity coordinates of (x=0.32, y=0.29) and color temperature of 6175K. These results suggest that Ca(7)Mg(2)P(6)O(24):Eu(2+),Mn(2+) phosphors could be a promising candidate for UV-converting white light-emitting diodes (LEDs).


Assuntos
Európio/química , Luz , Iluminação/instrumentação , Substâncias Luminescentes/química , Manganês/química , Fosfatos/química , Cor , Cristalografia por Raios X , Transferência de Energia , Luminescência , Fosfatos/efeitos da radiação , Fotoquímica , Espectrometria de Fluorescência , Temperatura Ambiente , Raios Ultravioleta
20.
Ultrason Sonochem ; 17(1): 228-33, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19501536

RESUMO

In this study, the structure and substructure of SiO(2)-Mg phosphate tungsten bronzes, MgPTB, (MgHPW(12)O(40).29H(2)O) obtained by ultrasonic spray pyrolysis method from a silica sol, and a MgPTB solution, obtained by the ion exchange method, as precursors were investigated. The mechanism of the formation of aerosol droplets is discussed. Phase composition, structure and substructure of SiO(2)-MgPTB particles were investigated by X-ray powder diffraction (XRPD) analysis, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Good agreement between the theoretically predicted values for the mean diameters of particles and subparticles (1.27 microm and 75.4 nm, respectively) and the experimentally obtained ones (1.17 microm and 65-90 nm) was found. This agreement confirms the applicability of the model to get a satisfactory prediction of the most important data related to the nano-structural design of SiO(2)-MgPTB powders.


Assuntos
Compostos de Magnésio/química , Compostos de Magnésio/efeitos da radiação , Nanoestruturas/química , Nanoestruturas/efeitos da radiação , Fosfatos/química , Fosfatos/efeitos da radiação , Dióxido de Silício/química , Dióxido de Silício/efeitos da radiação , Tungstênio/química , Tungstênio/efeitos da radiação , Gases/química , Gases/efeitos da radiação , Temperatura Alta , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Tamanho da Partícula , Doses de Radiação , Sonicação/métodos
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