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1.
JBRA Assist Reprod ; 28(1): 206-208, 2024 Feb 26.
Article in English | MEDLINE | ID: mdl-38091260

ABSTRACT

Despite the widespread use of transvaginal ultrasound-guided oocyte retrieval in assisted reproductive technology procedures, there is a lack of systematic data on the incidence and nature of its complications. This makes it difficult for healthcare providers to fully understand and manage the risks associated with the procedure, and for patients to make informed decisions about their care. Ureteral injuries and other complications during oocyte retrieval are important to consider and manage appropriately. Early ureterovaginal fistula is a rare but serious complication that can occur after oocyte collection by transvaginal ultrasound. It is important for medical professionals to be aware of this potential complication and to take appropriate measures to prevent and manage it. Minimally invasive treatments for ureterovaginal fistula can be effective in resolving the condition and minimize the risk of further complications. However, early diagnosis and prompt intervention are critical in achieving a successful outcome.


Subject(s)
Fistula , Oocyte Retrieval , Humans , Fistula/etiology , Oocyte Retrieval/adverse effects , Ultrasonography , Ultrasonography, Interventional/adverse effects
2.
Dalton Trans ; 53(2): 525-534, 2024 Jan 02.
Article in English | MEDLINE | ID: mdl-38051257

ABSTRACT

In this study, several methods were employed to investigate the electrical characteristics of ß-Ag2MoO4 systems, both Eu-doped and undoped, synthesized using the microwave-assisted hydrothermal method. The focus extended to understanding how synthesis time influences material defects, with doping fixed at 1%. A systematic shift in the silver vacancy (VAg) concentration was observed within the doped ß-Ag2MoO4 system. Specifically, this study demonstrated that the incorporation of Eu3+ into polycrystalline ß-Ag2MoO4 initially increases the VAg concentration. However, as the synthesis time progresses, the VAg concentration decreases, resulting in alterations in the resulting electrical properties, arising from the intricate interplay between the number of grain boundaries and carrier density. By combining information obtained from photoluminescence, positron annihilation lifetime spectroscopy, and impedance spectroscopy, a comprehensive conduction mechanism was formulated, shedding light on both doped and undoped ß-Ag2MoO4 systems.

4.
Int J Mol Sci ; 23(18)2022 Sep 13.
Article in English | MEDLINE | ID: mdl-36142511

ABSTRACT

In this work, α-Ag2-2xCuxWO4 (0 ≤ x ≤ 0.16) solid solutions with enhanced antibacterial (against methicillin-resistant Staphylococcus aureus) and antifungal (against Candida albicans) activities are reported. A plethora of techniques (X-ray diffraction with Rietveld refinements, inductively coupled plasma atomic emission spectrometry, micro-Raman spectroscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, field emission scanning electron microscopy, ultraviolet-visible spectroscopy, photoluminescence emissions, and X-ray photoelectron spectroscopy) were employed to characterize the as-synthetized samples and determine the local coordination geometry of Cu2+ cations at the orthorhombic lattice. To find a correlation between morphology and biocide activity, the experimental results were sustained by first-principles calculations at the density functional theory level to decipher the cluster coordinations and electronic properties of the exposed surfaces. Based on the analysis of the under-coordinated Ag and Cu clusters at the (010) and (101) exposed surfaces, we propose a mechanism to explain the biocide activity of these solid solutions.


Subject(s)
Disinfectants , Metal Nanoparticles , Methicillin-Resistant Staphylococcus aureus , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Disinfectants/pharmacology , Metal Nanoparticles/chemistry , Spectroscopy, Fourier Transform Infrared , X-Ray Diffraction
5.
Dalton Trans ; 51(30): 11346-11362, 2022 Aug 02.
Article in English | MEDLINE | ID: mdl-35815575

ABSTRACT

A systematic theoretical and experimental study was carried out to find a relationship between photoluminescence emissions and photocatalytic activity of Ag2SeO4 obtained by different synthesis methods (sonochemistry, ultrasonic probe, coprecipitation and microwave assisted hydrothermal synthesis). Experimental characterization techniques (XRD with Rietveld refinement, Raman, FTIR, UV-vis, XPS and photoluminescence spectroscopy) were used to elucidate its structural order at short, medium, and long ranges. Morphological analysis performed by FE-SEM showed distinct morphologies due to the different methods of synthesis. Based on density functional theory (DFT) calculations, it was possible to study in detail the Ag2SeO4 surface properties, including its surface energy, geometry, and electronic structure for the (100), (010), (001), (101), (011), (110), (111), (021), (012) and (121) surfaces. The equilibrium morphology of Ag2SeO4 was predicted as a truncated octahedron with exposed (111), (001), (010) and (011) surfaces. Photoluminescence emissions showed a band covering the visible spectrum, and the Ag2SeO4 obtained by the coprecipitation method presented the most intense band with a maximum in the red region. Photocatalytic results confirmed that Ag2SeO4 synthesized by the sonochemistry method is the best photocatalyst for rhodamine B degradation under UV light irradiation.

6.
Urol Case Rep ; 43: 102118, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35646600

ABSTRACT

Corpus cavernosum abscess is a rare infection of the genitourinary tract. In this case report, we present a 42-year-old patient admitted with pain and edema in the penile shaft twenty-four days after drainage by puncture of the cavernous body due to ischemic priapism. Al-Ghorab procedure together snake-maneuver and broad-spectrum antibiotic therapy were performed. Despite manifesting erectile dysfunction, he evolved without penile deviations.

7.
Sci Rep ; 12(1): 8118, 2022 05 17.
Article in English | MEDLINE | ID: mdl-35581241

ABSTRACT

In the current COVID-19 pandemic, the next generation of innovative materials with enhanced anti-SARS-CoV-2 activity is urgently needed to prevent the spread of this virus within the community. Herein, we report the synthesis of chitosan/α-Ag2WO4 composites synthetized by femtosecond laser irradiation. The antimicrobial activity against Escherichia coli, Methicilin-susceptible Staphylococcus aureus (MSSA), and Candida albicans was determined by estimating the minimum inhibitory concentration (MIC) and minimal bactericidal/fungicidal concentration (MBC/MFC). To assess the biocompatibility of chitosan/α-Ag2WO4 composites in a range involving MIC and MBC/MFC on keratinocytes cells (NOK-si), an alamarBlue™ assay and an MTT assay were carried out. The SARS-CoV-2 virucidal effects was analyzed in Vero E6 cells through viral titer quantified in cell culture supernatant by PFU/mL assay. Our results showed a very similar antimicrobial activity of chitosan/α-Ag2WO4 3.3 and 6.6, with the last one demonstrating a slightly better action against MSSA. The chitosan/α-Ag2WO4 9.9 showed a wide range of antimicrobial activity (0.49-31.25 µg/mL). The cytotoxicity outcomes by alamarBlue™ revealed that the concentrations of interest (MIC and MBC/MFC) were considered non-cytotoxic to all composites after 72 h of exposure. The Chitosan/α-Ag2WO4 (CS6.6/α-Ag2WO4) composite reduced the SARS-CoV-2 viral titer quantification up to 80% of the controls. Then, our results suggest that these composites are highly efficient materials to kill bacteria (Escherichia coli, Methicillin-susceptible Staphylococcus aureus, and the yeast strain Candida albicans), in addition to inactivating SARS-CoV-2 by contact, through ROS production.


Subject(s)
COVID-19 , Chitosan , Escherichia coli Infections , Staphylococcal Infections , Anti-Bacterial Agents/pharmacology , Candida albicans , Chitosan/pharmacology , Escherichia coli , Humans , Lasers , Microbial Sensitivity Tests , Pandemics , SARS-CoV-2 , Staphylococcus aureus
9.
Mental ; 13(23): 52-78, jan.-jun. 2021. ilus
Article in Portuguese | LILACS-Express | LILACS, Index Psychology - journals | ID: biblio-1351113

ABSTRACT

Ao partir do pressuposto de que a psicopatologia possui um caráter transitório, e diante das discussões acerca do DSM-5, questiona-se: a quem serve as alterações das classes diagnósticas, em especial as dos Transtornos de Humor? Responder a essa questão passa por refletir sobre os modos de se lidar com o sofrimento psíquico na sociedade hodierna. Nesses termos, objetiva-se analisar criticamente as transformações da classe dos Transtornos de Humor sofridas na última versão do DSM. Utilizou-se como método a pesquisa bibliográfica de caráter exploratório e comparativo. Depreendeu-se que a classe diagnóstica do Transtorno de Humor presente no DSM-IV foi extinta do DSM-5 e suas categorias diagnósticas originaram duas novas classes: Transtorno Bipolar e Transtornos Relacionados e Transtornos Depressivos. Concluiu-se que as alterações referentes aos Transtornos de Humor sugerem uma tendência, cada vez mais, crescente de se patologizar estados de ânimos decorrentes de condições de sofrimento normais do sujeito. Por outro lado, a sociedade contemporânea parece fornecer as insígnias próprias para a constituição subjetiva de indivíduos altamente fragilizados especialmente no tocante aos estados de humor.


Starting from the assumption that psychopathology has a transitory character, and in view of the discussions about the DSM-5, the question is: who serves the alterations of the diagnostic classes, especially those of Mood Disorders? Answering this ques-tion involves reflecting on the ways of dealing with psychological suffering in today's society. In these terms, the objective is to critically analyze the changes in the class of Mood Disorders suffered in the latest version of the DSM. Exploratory and comparative bibliographic research was used as a method. It appeared that the diagnostic class of Mood Disorder present in DSM-IV was extinguished from DSM-5 and its diagnostic categories gave rise to two new classes: Bipolar Disorder and Related Disorders and Depressive Disorders. It was concluded that the alterations referring to Mood Disorders suggest an increasing tendency to pathologize states of mind resulting from the subject's normal suffering conditions. On the other hand, contemporary society seems to provide its own insignia for the subjective constitution of highly fragile individuals, especially with regard to mood states.


Partiendo del supuesto de que la psicopatología tiene un carácter transitorio, y a la vista de las discusiones sobre el DSM-5, la pregunta es: ¿quién atiende las alteraciones de las clases diagnósticas, especialmente las de los trastornos del estado de ánimo? Responder a esta pregunta implica reflexionar sobre las formas de afrontar el sufrimiento psicológico en la sociedad actual. En estos términos, el objetivo es analizar críticamente las transformaciones de la clase de Trastornos del Estado de Ánimo sufridas en la última versión del DSM. Se utilizó como método la investigación bibliográfica exploratoria y comparativa. Parecía que la clase diagnóstica de trastorno del estado de ánimo presente en el DSM-IV se extinguió del DSM-5 y sus categorías de diagnóstico dieron lugar a dos nuevas clases: trastorno bipolar y trastornos relacionados y trastornos depresivos. Se concluyó que las alteraciones referidas a los Trastornos del Estado de Ánimo sugieren una tendencia creciente a patologizar los estados de ánimo derivados de las condiciones normales de sufrimiento del sujeto. Por otro lado, la sociedad contemporánea parece proporcionar su propia insignia para la constitución subjetiva de individuos muy frágiles, especialmente en lo que respecta a los estados de ánimo.

11.
Inorg Chem ; 60(8): 5937-5954, 2021 Apr 19.
Article in English | MEDLINE | ID: mdl-33769807

ABSTRACT

In this paper, we report the synthesis of silver selenite (Ag2SeO3) by different methods [sonochemistry, ultrasonic probe, coprecipitation, and microwave-assisted hydrothermal methods]. These microcrystals presented a structural long-range order as confirmed by X-ray diffraction (XRD) and Rietveld refinements and a structural short-range order as confirmed by Fourier transform infrared (FTIR) and Raman spectroscopies. X-ray photoelectron spectroscopy (XPS) provided information about the surface of the samples indicating that they were pure. The microcrystals presented different morphologies and sizes due to the synthesis method as observed by field emission scanning electron microscopy (FE-SEM). The optical properties of these microcrystals were evaluated by ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL) measurements. Thermal analysis confirmed the temperature stability of the as-synthetized samples. Further trapping experiments prove that the holes and hydroxyl radicals, to a minor extent, are responsible for the photocatalytic reactions. The experimental results are sustained by first-principles calculations, at the density functional theory (DFT) level, to decipher the structural parameters, electronic properties of the bulk, and surfaces of Ag2SeO3. By matching the experimental FE-SEM images and theoretical morphologies, we are capable of finding a correlation between the morphology and photocatalytic activity, along with photodegradation of the Rhodamine B dye under UV light, based on the different numbers of unsaturated superficial Ag and Se cations (local coordination, i.e., clusters) of each surface.

12.
ACS Appl Mater Interfaces ; 13(3): 4605-4617, 2021 Jan 27.
Article in English | MEDLINE | ID: mdl-33443996

ABSTRACT

The magnetic properties and ozone (O3) gas-sensing activity of zinc ferrite (ZnFe2O4) nanoparticles (NPs) were discussed by the combination of the results acquired by experimental procedures and density functional theory simulations. The ZnFe2O4 NPs were synthesized via the microwave-assisted hydrothermal method by varying the reaction time in order to obtain ZnFe2O4 NPs with different exposed surfaces and evaluate the influence on its properties. Regardless of the reaction time employed in the synthesis, the zero-field-cooled and field-cooled magnetization measurements showed superparamagnetic ZnFe2O4 NPs with an average blocking temperature of 12 K. The (100), (110), (111), and (311) surfaces were computationally modeled, displaying the different undercoordinated surfaces. The good sensing activity of ZnFe2O4 NPs was discussed in relation to the presence of the (110) surface, which exhibited low (-0.69 eV) adsorption enthalpy, promoting reversibility and preventing the saturation of the sensor surface. Finally, the O3 gas-sensing mechanism could be explained based on the conduction changes of the ZnFe2O4 surface and the increase in the height of the electron-depletion layer upon exposure toward the target gas. The results obtained allowed us to propose a mechanism for understanding the relationship between the morphological changes and the magnetic and O3 gas-sensing properties of ZnFe2O4 NPs.

13.
ACS Omega ; 5(25): 14879-14889, 2020 Jun 30.
Article in English | MEDLINE | ID: mdl-32637762

ABSTRACT

The modification of CeO2 with rare-earth elements opens up a wide range of applications as biomedical devices using infrared emission as well as magnetic and gas-sensing devices, once the structural, morphological, photoluminescent, magnetic, electric, and gas-sensing properties of these systems are strongly correlated to quantum electronic transitions between rare-earth f-states among defective species. Quantitative phase analysis revealed that the nanopowders are free from secondary phases and crystallize in the fluorite-type cubic structure. Magnetic coercive field measurements on the powders indicate that the substitution of cerium with lanthanum (8 wt %), in a fluorite-type cubic structure, created oxygen vacancies and led to a decrease in the fraction of Ce species in the 3+ state, resulting in a stronger room-temperature ferromagnetic response along with high coercivity (160 Oe). In addition to the magnetic and photoluminescent behavior, a fast response time (5.5 s) was observed after CO exposure, indicating that the defective structure of ceria-based materials corresponds to the key of success in terms of applications using photoluminescent, magnetic, or electrical behaviors.

14.
Article in English | LILACS-Express | LILACS, Index Psychology - journals | ID: biblio-1098461

ABSTRACT

Abstract This text aims to establish relationships between drugs and so-called gadgets from this social call to consumption whether they are objects in general, or drugs in particular. We carried out a bibliographic study using, mainly, books, articles, and dissertations referring to the subject with the intention to reach this objective. We also developed this research in three parts, which highlight the critical points of contemporary psychopathology. The first one deals with how the consumption of objects has become an object that consumes the subject. We then traced the legitimation of the subject "compressed" in the current discourse. Finally, we highlighted the gadgets and the new way of life for the contemporary people.


Resumo Este texto tem por objetivo estabelecer as relações entre os medicamentos e os chamados gadgets a partir do chamado social ao consumo (tanto de objetos, em geral, quanto de fármacos, em particular). Para tanto, realizamos um estudo bibliográfico a partir de livros, artigos e dissertações referentes ao assunto. Assim, desenvolvemos esta investigação em três partes, as quais evidenciam os pontos críticos da psicopatologia contemporânea. A primeira delas aborda como o consumo de objetos transformou-se em objeto (con)sumido. Em seguida, rastreamos a legitimação do sujeito "comprimido" no discurso atual. Por fim, evidenciamos os gadgets e os novos modos de viver do contemporâneo.

15.
Ágora (Rio J. Online) ; 21(1): 12-22, jan.-abr. 2018.
Article in Portuguese | LILACS, Index Psychology - journals | ID: biblio-904812

ABSTRACT

O artigo aborda as relações de aproximação e distanciamento entre a teoria queer e a Psicanálise, na cena contemporânea. Reconhece o valor da teoria queer para os debates sobre as transformações da sexualidade e das performances de gênero na atualidade e, por outro lado, aponta como a Psicanálise - bem diferentemente do que é proposto por pensadores queer - contribui para este campo, especialmente a partir das elaborações de Jacques Lacan sobre a sexuação.


This article deals with the relationship of approach and distance between queer theory and psychoanalysis, in the contemporary scene. It recognizes the value of the queer theory to the discussions about the transformation of sexuality and gender performances nowadays and, on the other hand, point out as psychoanalysis - very different to what is proposed by queer thinkers - contributes to this field, especially from Jacques Lacan´s elaborations about sexuation.


Subject(s)
Psychoanalysis , Sexual Behavior , Sexuality
16.
Int Braz J Urol ; 43(6): 1195, 2017.
Article in English | MEDLINE | ID: mdl-28379670

ABSTRACT

A 41-year-old male presented at Emergency Department (ED) with right flank pain associated with hematuria for 3 days. Patient had a previous history of nephrolithiasis. The physical examination and blood tests were normal. Urine analyses showed haematuria > 1.000.000/µL. After clinical evaluation, a computer tomography (CT) showed right ureteral dilata¬tion caused by a 5 mm proximal stone and a distal intraluminal mass of 8 cm in length. In this setting, an ureteroscopic biopsy was performed and revealed a large polypoid lesion histologically suggestive of fibroepithelial polyp. Due to technical difficulties (intraluminal mass length and technical issue for the passage of guidewire) and after discussing all available minimally invasive options, we opted for a laparoscopic approach. Instead of ureterectomy of the affected segment of the ureter, as classically performed, we proceeded with an ureterotomy, blunt dissection of the tumor and ureterolithotomy, with complete removal of the mass. This approach did not require ureteral anastomosis and the ureteral dilatation facilitated its primary closure. No complications occurred, even after 3 years of follow-up.


Subject(s)
Neoplasms, Fibroepithelial/surgery , Polyps/surgery , Ureteral Neoplasms/surgery , Adult , Humans , Male , Neoplasms, Fibroepithelial/diagnostic imaging , Polyps/diagnostic imaging , Tomography, X-Ray Computed , Ureteral Neoplasms/diagnostic imaging , Ureteroscopy/methods
17.
Apunts, Med. esport (Internet) ; 52(193): 23-28, ene.-mar. 2017. tab
Article in Spanish | IBECS | ID: ibc-162147

ABSTRACT

Este estudio tuvo como objetivo comparar la respuesta de la presión arterial en los hombres normotensos entrenados realizando sesiones experimentales con cargas del 60 y el 80% de una repetición máxima. Diez participantes se sometieron a 3 condiciones experimentales: P60 (sesión realizada con el 60%); P80 (sesión realizada con el 80% de una repetición máxima [1RM]), y CONT (solo las evaluaciones de la presión arterial en el estado de reposo durante 60 min [intervalos de 10 min]). El protocolo experimental se llevó a cabo con 3 series, con intervalo de 3 min entre las series y los ejercicios. La presión arterial se midió antes y a los 10, 20, 30, 40, 50 y 60 min después de la sesión de entrenamiento. Los resultados mostraron que ambos protocolos indujeron hipotensión postejercicio (p < 0,05) en comparación con los valores en reposo. El P80 mostró una mayor magnitud y duración de la hipotensión postejercicio en comparación con el protocolo P60 (p < 0,05). En conclusión, el entrenamiento de fuerza es eficaz para proporcionar hipotensión postejercicio independientemente de la intensidad de la carga. Por lo tanto, en esta investigación es importante mostrar la relevancia del control de la intensidad de la carga durante el desarrollo de los programas de entrenamiento de fuerza. El entrenamiento de fuerza con el 60% de 1RM puede ser tan eficaz como los protocolos con 80% de 1RM para prevenir la presión arterial alta en los hombres


This study aimed to compare the blood pressure responses in normotensive-trained men following resistance training (RT) experimental sessions with loads of 60% and 80% of a one-repetition maximum. Ten participants underwent three experimental condition: (P60) - session adjusted with 60%, (P80) - session adjusted with 80% of 1 repetition maximum (1RM) and, (CONT) - conly blood pressure assessments in rest condition for 60 min (intervals of 10 min). The resistance training design was adjusted with 3-sets, 3-min rest interval length between sets and exercises. Blood pressure was measured before, and at 10, 20, 30, 40, 50, and 60 min after the training session. The results showed that both protocols induce post-exercise hypotension (p < 0.05) compared to the rest values. The P80 showed greater magnitude and duration of post exercise hypotension when compared with P60 protocol (p < 0.05). In conclusion, resistance training is effective to provide a post exercise hypotension independent of the load intensities. This study is important to show the importance of control of the load intensity during development of resistance training programs and, the RT with 60% of 1RM can be as effective as protocols with 80% of 1RM to prevent the high blood pressure


Subject(s)
Humans , Male , Physical Conditioning, Human/physiology , Resistance Training , Arterial Pressure/physiology , Cardiovascular Physiological Phenomena , Hypertension/prevention & control
18.
Fractal rev. psicol ; 23(2): 353-365, mayo-ago. 2011.
Article in Portuguese | LILACS | ID: lil-599740

ABSTRACT

O artigo contextualiza uma tradição que se apresenta de maneira recorrente nas práticas clínicas da psicologia e da saúde mental: o Mentalismo. O Mentalismo pressupõe uma concepção interiorizada do sujeito em prol de modelos instrumentais de clínica. A partir da crítica ao Mentalismo, os autores examinam outras possibilidades de se lidar não mais com o sujeito essencializado, porém, com os complexos processos de subjetivação. Esta é uma perspectiva clínica que recorrendo a Deleuze, Guattari e à Filosofia da Diferença oferece estratégias mais condizentes com a complexidade do mundo contemporâneo, introduzindo debates éticos, políticos e estéticos na dimensão psíquica.


This present article contextualises and examines a tradiction that presents itself recurrent way in the midst of clinical practice of psychology and mental health: Mentalism. The Mentalism assumes an internalized and essencialized conception of the subject in favor of instrumental models of clinica. From the criticism on mentalism the authors examine other possibilities to deal with no more the essentialized subject, however, with the complex process of subjectivity. This is a clinical perspective that resorting to Deleuze, Guattari and to Philosophy of Difference offers conception, strategies more commensurate to the complexity of the contemporary world, introducing ethical, political and aesthetic discussions in the psychic dimension.


Subject(s)
Humans , Individuation
19.
Fractal rev. psicol ; 23(2): 353-365, maio-ago. 2011.
Article in Portuguese | Index Psychology - journals | ID: psi-49850

ABSTRACT

O artigo contextualiza uma tradição que se apresenta de maneira recorrente nas práticas clínicas da psicologia e da saúde mental: o Mentalismo. O Mentalismo pressupõe uma concepção interiorizada do sujeito em prol de modelos instrumentais de clínica. A partir da crítica ao Mentalismo, os autores examinam outras possibilidades de se lidar não mais com o sujeito essencializado, porém, com os complexos processos de subjetivação. Esta é uma perspectiva clínica que recorrendo a Deleuze, Guattari e à Filosofia da Diferença oferece estratégias mais condizentes com a complexidade do mundo contemporâneo, introduzindo debates éticos, políticos e estéticos na dimensão psíquica.(AU)


This present article contextualises and examines a tradiction that presents itself recurrent way in the midst of clinical practice of psychology and mental health: Mentalism. The Mentalism assumes an internalized and essencialized conception of the subject in favor of instrumental models of clinica. From the criticism on mentalism the authors examine other possibilities to deal with no more the essentialized subject, however, with the complex process of subjectivity. This is a clinical perspective that resorting to Deleuze, Guattari and to Philosophy of Difference offers conception, strategies more commensurate to the complexity of the contemporary world, introducing ethical, political and aesthetic discussions in the psychic dimension.(AU)


Subject(s)
Humans , Individuation
20.
Phys Chem Chem Phys ; 12(27): 7566-79, 2010 Jul 21.
Article in English | MEDLINE | ID: mdl-20523931

ABSTRACT

A combined experimental and theoretical investigation on the photoluminescence properties of SrTiO(3) (ST) and SrSm(0.01)Ti(0.99)O(3) (ST_Sm) nanostructures is presented in this work. The nanocrystalline powders were prepared by the polymeric precursor method, and the order-disorder behavior of this material was investigated by means of X-ray diffraction (XRD), spectral absorbance (UV-vis), transmission electron microscopy (TEM) images, electron paramagnetic resonance (EPR) and photoluminescence (PL) experimental techniques. The decrease in the broad PL emission band of ST and ST_Sm powders measured at room temperature indicates an increase in the structural order as the annealing temperature increases, i.e. characteristic samarium peaks intensify as the structural order increases in ST_Sm samples. The interactions of the network clusters that form the ST and ST_Sm structures were evaluated by means of the ab initio periodic method at the density functional theory (DFT) level with the hybrid nonlocal B3LYP approximation. The symmetry-breaking process that leads to the presence of non-ideal [TiO(6)] and [SrO(12)] clusters, as well as the relationship between these clusters, provides favorable structural and electronic conditions for the appearance of PL phenomena.

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