RESUMEN
We report the results of a study that was conducted to investigate the recombination paths of photoexcited charge carriers in GeSn thin films. The charge carrier lifetime was predicted as a function of temperature from a description of photoconductivity transients, assuming co-influence of Shockley-Read-Hall and radiative carrier recombination paths. We identify that dislocations are the source of a band of electronic states with the highest occupied state at E V + (85÷90) meV that acts as Shockley-Read-Hall centers determining the charge carrier lifetime. The photoluminescence (PL) and photoconductivity spectroscopy have been applied to distinguish between the contribution of both band-to-band and dislocation-related electron transitions. The PL band was found to demonstrate a low-energy shift of about 80 ± 20 meV relative to the edge of the photoconductivity spectra in the indirect bandgap GeSn films with dislocations. The role of a different nature deeper acceptor level at E V + (140 ÷ 160) meV in the recombination processes of the GeSn layers with better structural quality and the Sn content higher than 4% was discussed. This detailed understanding of the recombination processes is of critical importance for developing GeSn/Ge-based optoelectronic devices.
RESUMEN
Al2O3:SiOC nanocomposites were synthesized by thermal treatment of fumed alumina nanoparticles modified by phenyltrimethoxysilane. The effect of annealing temperature in inert ambient on structure and photoluminescence of modified alumina powder was studied by IR spectroscopy as well as photoluminescence spectroscopy with ultraviolet and X-ray excitation. It is demonstrated that increase of annealing temperature results in formation of silica precipitates on the surface of alumina particles that is accompanied by development and spectral evolution of visible photoluminescence. These observations are discussed in terms of structural transformation of the surface of Al2O3 particles.
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A massage with the potent counter-inflammatory material, cerium dioxide nanoparticles, is promising and the antioxidant properties of CeO2 are considered the main, if not the only, mechanism of this action. Nevertheless, the elimination of ceria nano-particles from the organism is very slow and there is a strong concern for toxic effect of ceria due to its accumulation. To overcome this problem, we engineered a combined material in which cerium nanoparticles were immobilized on the surface of silica nanoparticles (CeO2 NP), which is shown to be easily removed from an organism and could be used as carriers for nano-ceria. In our study particle size was 220±5nm, Zeta-potential -4.5mV (in water), surface charge density -17.22µC/cm2 (at pH 7). Thirty-six male Wistar rats, 5 months old and 250-290g were divided into four groups: 1) control; 2) CeO2 NP treatment; 3) experimental pneumonia (i/p LPS injection, 1mg/kg); and 4) experimental pneumonia treated with CeO2 NP (4 times during the study in dosage of 0.6mg/kg with an orogastric catheter). Gas exchange and pulmonary ventilation were measured four times: 0, 1, 3 and 24h after LPS injection in both untreated and CeO2 NP-treated animals. The mRNA of TNF-α, Il-6, and CxCL2 were determined by RT-PCR. ROS-generation in blood plasma and lung tissue homogenates were measured by means of lucigenin- and luminol-enhanced chemiluminescence. Endotoxemia in the acute phase was associated with: (1) pathological changes in lung morphology; (2) increase of ROS generation; (3) enhanced expression of CxCL2; and (4) a gradual decrease of VO2 and VE. CeO2 NP treatment of intact animals did not make any changes in all studied parameters except for a significant augmentation of VO2 and VE. CeO2 NP treatment of rats with pneumonia created positive changes in diminishing lung tissue injury, decreasing ROS generation in blood and lung tissue and decreasing pro-inflammatory cytokine expression (TNF-α, Il-6 and CxCL2). Oxygen consumption in this group was increased compared to the LPS pneumonia group. In our study we have shown anti-inflammatory and antioxidant effects of CeO2 NP. In addition, this paper is the first to report that CeO2 NP stimulates oxygen consumption in both healthy rats, and rats with pneumonia. We propose the key in understanding the mechanisms behind the phenomena lies in the property of CeO2 NP to scavenge ROS and the influence of this potent antioxidant on mitochondrial function. The study of biodistribution and elimination of СеÐ2NP is the purpose of our ongoing study.
Asunto(s)
Antiinflamatorios no Esteroideos/administración & dosificación , Antioxidantes/administración & dosificación , Cerio/administración & dosificación , Modelos Animales de Enfermedad , Portadores de Fármacos/administración & dosificación , Nanopartículas/efectos adversos , Neumonía/tratamiento farmacológico , Animales , Antiinflamatorios no Esteroideos/uso terapéutico , Antioxidantes/efectos adversos , Antioxidantes/uso terapéutico , Cerio/efectos adversos , Cerio/uso terapéutico , Citocinas/sangre , Citocinas/genética , Citocinas/metabolismo , Portadores de Fármacos/efectos adversos , Portadores de Fármacos/uso terapéutico , Regulación de la Expresión Génica/efectos de los fármacos , Lipopolisacáridos , Pulmón/efectos de los fármacos , Pulmón/metabolismo , Pulmón/patología , Pulmón/fisiopatología , Masculino , Nanopartículas/química , Estrés Oxidativo/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , Tamaño de la Partícula , Neumonía/metabolismo , Neumonía/patología , Neumonía/fisiopatología , Ventilación Pulmonar/efectos de los fármacos , Ratas Wistar , Especies Reactivas de Oxígeno/antagonistas & inhibidores , Especies Reactivas de Oxígeno/metabolismo , Dióxido de Silicio/efectos adversos , Dióxido de Silicio/química , Propiedades de Superficie , Volumen de Ventilación Pulmonar/efectos de los fármacosRESUMEN
Silicon nanoparticles (SiNPs) prepared by mechanical grinding of luminescent porous silicon were coated with a biopolymer (dextran) and investigated as a potential theranostic agent for bioimaging and sonodynamic therapy. Transmission electron microscopy, photoluminescence and Raman scattering measurements of dextran-coated SiNPs gave evidence of their enhanced stability in water. In vitro experiments confirmed the lower cytotoxicity of the dextran-coated NPs in comparison with uncoated ones, especially for high concentrations of about 2 mg ml-1. Efficient uptake of the NPs by cancer cells was found using bioimaging in the optical transmittance and photoluminescence modes. Treatment of the cells with uptaken SiNPs by therapeutic ultrasound for 5-20 min resulted in a strong decrease in the number of living cells, while the total number of cells remained nearly unchanged. The obtained data indicate a 'mild' effect of the combined action of ultrasonic irradiation and SiNPs on cancer cells. The observed results reveal new opportunities for controlling the photoluminescent and sonosensitizing properties of silicon-based NPs for applications in the diagnostics and mild therapy of cancer.
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Materiales Biocompatibles Revestidos/química , Nanopartículas/toxicidad , Neoplasias/patología , Silicio/toxicidad , Nanomedicina Teranóstica/métodos , Ondas Ultrasónicas , Células 3T3-L1 , Animales , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Dextranos/química , Perros , Humanos , Luminiscencia , Ratones , Nanopartículas/química , Nanopartículas/ultraestructura , Espectrometría Raman , Factores de TiempoRESUMEN
The electronic tongue based on the array of low selective photovoltaic (PV) sensors and principal component analysis is proposed for detection of various alcohol solutions. A sensor array is created at the forming of p-n junction on silicon wafer with porous silicon layer on the opposite side. A dynamical set of sensors is formed due to the inhomogeneous distribution of the surface recombination rate at this porous silicon side. The sensitive to molecular adsorption photocurrent is induced at the scanning of this side by laser beam. Water, ethanol, iso-propanol, and their mixtures were selected for testing. It is shown that the use of the random dispersion of surface recombination rates on different spots of the rear side of p-n junction and principal component analysis of PV signals allows identifying mentioned liquid substances and their mixtures.
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This study presents the data on the polymorphisms of the serotonin system genes (5-HTTL, 5-HT1A, 5-HT2A, and MAOA) in male and female wrestlers and in the control group. The population genetics analysis of the 5HTTL gene showed the highest frequency of the SS genotype 5-HTTLPR in sportsmen (p = 0.04), as well as the trend toward higher frequency of united genotypes of the locus of 5-HTTLPR VNTR and SNP rs25531--SASA (p = 0.06) in comparison with the control group. As for the polymorphisms for other genes 5-HT1A (rs6295), 5-HT2A (rs6311), and MAOA (VNTR), we found no significant differences between the groups tested. Using the NEO PI-R questionnaire we analyzed the possible correlations between the genotypes and the psychological traits in our samples. It was demonstrated that the athletic success in elite sportsmen was associated with lower openness to experience and higher conscientiousness. The interaction effect of the gender and 5-HT2A on the self-rating for openness to experience, interaction effect of the level of the sport success and 5-HT2A, and the interaction effect of the gender and 5-HT1A genotype on self-reported conscientiousness were observed as a trend.
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Monoaminooxidasa/genética , Personalidad/genética , Polimorfismo de Nucleótido Simple , Receptor de Serotonina 5-HT1A/genética , Receptor de Serotonina 5-HT2A/genética , Proteínas de Transporte de Serotonina en la Membrana Plasmática/genética , Lucha/psicología , Atletas/psicología , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Repeticiones de Minisatélite , Factores SexualesRESUMEN
An electronic tongue concept based on 2D mapping of photogenerated charge carrier lifetimes in silicon put in contact with different liquids is reported. Such method based on intrinsic sensitivity of the silicon surface states to the surrounding studied liquids allows creation of their characteristic electronic fingerprints. To increase recognition reliability, a set of characteristic fingerprints for a given liquid/silicon interface is proposed to be recorded at different bias voltages. The applicative potential of our sensing concept was demonstrated for different spirits and water samples.
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Bebidas/análisis , Técnicas Electroquímicas/instrumentación , Modelos Biológicos , Silicio/química , Lengua/fisiología , Análisis de Componente Principal , Propiedades de SuperficieRESUMEN
Clinical signs characteristic for early central choroidal melanoma (42 patients) and late stage age-related macula degeneration according to AREDS (47 patients) were determined in 89 patients. These signs allow to differentiate between tumor and degenerative process thus providing appropriate treatment.
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Neoplasias de la Coroides/diagnóstico , Técnicas de Diagnóstico Oftalmológico , Degeneración Macular/diagnóstico , Melanoma/diagnóstico , Neoplasias de la Úvea/diagnóstico , Anciano , Neoplasias de la Coroides/patología , Neoplasias de la Coroides/fisiopatología , Diagnóstico Diferencial , Progresión de la Enfermedad , Femenino , Humanos , Degeneración Macular/patología , Degeneración Macular/fisiopatología , Masculino , Melanoma/patología , Melanoma/fisiopatología , Selección de Paciente , Índice de Severidad de la Enfermedad , Neoplasias de la Úvea/patología , Neoplasias de la Úvea/fisiopatologíaRESUMEN
An original plasmonic nano-Ag/SiN(x) substrate was elaborated to strongly enhance the nonlinear response of SiC NPs for the first time. A plasmon-induced two order of magnitude increase of second-harmonic generation and two-photon excited photoluminescence was experimentally achieved. The measured enhancement factors were correlated with local field intensities theoretically estimated by finite-difference time-domain calculations. The obtained plasmon-enhanced nonlinear response of the SiC nanostructures make them promising in nonlinear optics applications.
RESUMEN
The application of nanostructured luminescent silicon nitride (SiN(X)) thin films for label-free cell imaging is reported for the first time. Different strong local fields ensured by various molecules concentrated in various cell compartments can lead to the creation of preferential electronic conditions for radiative recombination of photogenerated charge carriers via a given electronic channel. Thus, highly contrasted multicolor luminescent cell imaging under one photon excitation becomes possible. The described label-free bio-imaging approach has good compatibility with fluorescence optical microscopy, and allows rapid and efficient cell imaging and cell line recognition.
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Nanoestructuras/química , Compuestos de Silicona/química , Células 3T3 , Animales , Línea Celular Tumoral , Color , Humanos , Concentración de Iones de Hidrógeno , Ratones , Microscopía Confocal , Fotones , Puntos CuánticosRESUMEN
UNLABELLED: The objective of this study is to develop a marker panel of abnormalities of immune regulatory systems and cell genome in patients with gastric cancer for assessment of efficacy of surgical treatment in combination with pharmaco-nutritional therapy in early postoperative period. MATERIALS AND METHODS: Expression of p53, sFAS, FASL, CEA, and CA 19-9, nutritial status, as well as incidence of purulent-septic complications in early postoperative period were determined in 40 patients with gastric cancer (21 patients--the test group and 19 patients--the comparative group) prior to a curative surgical intervention, postoperative days 1 and 7, while the pharmaco-nutritional therapy (the test group) or partial parenteral nutrition (the comparative group) has been performed. RESULTS: The pharmaco-nutritional therapy significantly decreases in activity of tumor suppressing genome, lymphocyte apoptosis, expression of oncology-associated markers, incidence of purulent-septic complications, as well as exacerbation risk for hypotrophy in patients with gastric cancer in early postoperative period. CONCLUSION: To assess the efficacy of the surgical intervention performed in patients with gastric cancer, an expression of mutant p53 and markers of lymphocyte apoptosis (sFAS/FASL) is reasonable to be evaluated together with determination of oncomarkers (CEA and CA 19-9).
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Biomarcadores de Tumor/sangre , Estado Nutricional , Apoyo Nutricional/métodos , Neoplasias Gástricas/cirugía , Anciano , Antígeno CA-19-9/sangre , Antígeno Carcinoembrionario/sangre , Proteína Ligando Fas/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Soluciones para Nutrición Parenteral , Valor Predictivo de las Pruebas , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/terapia , Proteína p53 Supresora de Tumor/sangre , Receptor fas/sangreRESUMEN
Covalent grafting of amino groups onto the carboxylic acid functionalities, naturally covering the surface of fluorescent nanoparticles produced from silicon carbide (SiC NPs), allowed tuning of their surface charge from negative to highly positive. Incubating 3T3-L1 fibroblast cells with differently charged SiC NPs demonstrates the crucial role of the charge in cell fluorescent targeting. Negatively charged SiC NPs concentrate inside the cell nuclei. Close to neutrally charged SiC NPs are present in both cytoplasm and nuclei while positively charged SiC NPs are present only in the cytoplasm and are not able to move inside the nuclei. This effect opens the door for the use of SiC NPs for easy and fast visualization of long-lasting biological processes taking place in the cell cytosol or nucleus as well as providing a new long-term cell imaging tool. Moreover, here we have shown that the interaction between charged NPs and nuclear pore complex plays an essential role in their penetration into the nuclei.
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Colorantes Fluorescentes/análisis , Nanopartículas/análisis , Poro Nuclear/metabolismo , Proteínas/metabolismo , Células 3T3-L1 , Aminas/química , Animales , Compuestos Inorgánicos de Carbono/química , Ácidos Carboxílicos/química , Núcleo Celular/química , Citoplasma/química , Colorantes Fluorescentes/química , Ratones , Nanopartículas/química , Poro Nuclear/química , Tamaño de la Partícula , Transporte de Proteínas , Compuestos de Silicona/química , Espectrometría de Fluorescencia , Espectroscopía Infrarroja por Transformada de Fourier , Coloración y Etiquetado , Electricidad Estática , Propiedades de SuperficieRESUMEN
Size tuning of silicon (Si) nanoparticles (NPs) with the use of meso-porous silicon (meso-PS) free-standing layers is reported for the first time. Accumulation of Si NPs inside the membrane pores during the filtering process (NP transport through the meso-PS) leads to an auto-filtration effect (called Si-by-Si (SBS) filtration) allowing more efficient size selection of the NPs. General complex fractal shape and surface chemistry of the whole porous network, layer thickness as well as a given initial NP size dispersion determine final size of the NPs in the filtered solution. Moreover, quantum of step-like NP size increasing equal to 0.12 nm was found.
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Luminiscencia , Membranas Artificiales , Nanopartículas/química , Silicio/química , Tamaño de la Partícula , Porosidad , Propiedades de SuperficieRESUMEN
Localization of quantum dots (QDs) in the vicinity of metal nanoparticles (NPs) is known as one of the most efficient ways to increase their photoluminescence (PL). Despite the important recent advances achieved in II-VI QDs, only a seven-fold plasmon-induced PL enhancement is reported for Si QDs. In our paper we show that the plasmon-induced strong local PL enhancement of Si QDs in an SiN matrix can reach a 60-fold gain level. This important result was achieved on original tunable "nano-Ag/SiN(X)" plasmonic structures. In particular, we show that (i) localization of Si QDs in hot spot regions created by several randomly arranged Ag NPs and (ii) careful tuning of the multi-polar plasmon bands of Ag NPs to match resonant absorption and emission wavelengths of Si QDs, lead to the important enhancement of their PL intensity.
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Nutrition support and molecular-genetic markers of the immune system at patients with complicated forms of gastric pathology. In this study presented results of surgery clinic of and oncology faculty SGMU to improve treatment patients with acute pancreatitis, and various forms of pancreonecrozis, through a balanced Threpsology support and operational gastrointestinal endoscopy.
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Colangiopancreatografia Retrógrada Endoscópica , Nutrición Enteral/métodos , Pancreatitis/terapia , Esfinterotomía Endoscópica , Enfermedad Aguda , Adulto , Bilirrubina/análisis , Diagnóstico Precoz , Femenino , Humanos , Lipasa/análisis , Masculino , Persona de Mediana Edad , Pruebas de Función Pancreática , Pancreatitis/diagnóstico , Pancreatitis/etiología , Pancreatitis/cirugía , Pancreatitis Aguda Necrotizante/diagnóstico , Pancreatitis Aguda Necrotizante/etiología , Pancreatitis Aguda Necrotizante/cirugía , Pancreatitis Aguda Necrotizante/terapia , Resultado del Tratamiento , Adulto Joven , alfa-Amilasas/sangreRESUMEN
In this article the role of immunoregulative system and cellular genome (p53 and sFAS/FASL) pathology biomarkers and oncological markers (cancer fetal antigene and CA19-9) was estimated in results of surgical treatment in complex with the various kinds of a clinical nutrition in the early postoperative period after colon cancer.
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Biomarcadores de Tumor/metabolismo , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/terapia , Proteína Ligando Fas/metabolismo , Nutrición Parenteral/métodos , Receptor fas/metabolismo , Anciano , Biomarcadores de Tumor/genética , Neoplasias Colorrectales/genética , Proteína Ligando Fas/genética , Femenino , Genoma Humano , Humanos , Masculino , Persona de Mediana Edad , Cuidados Posoperatorios , Estudios Retrospectivos , Receptor fas/genéticaRESUMEN
This study examines whether a relation exists between rapid atmospheric pressure fluctuations, attributed to the far infrasound frequency range (APF), and a number of emergency transport events coded as circulatory system diseases (EEC). Over an entire year, the average integral amplitudes of APF in the range of periods from 3 s to 120 s over each hour (HA) were measured. Daily dynamics of HA averaged over the year revealed a wave shape with smooth increase from night to day followed by decrease from day to night. The total daily number of EEC within the city of Kiev, Ukraine, was related to the daily mean of HA (DHA) and to the ratio of HA averaged over the day time to HA averaged over the night time (Rdn), and was checked for confounding effects of classical meteorological variables through non-parametric regression algorithms. The number of EEC were significantly higher on days with high DHA (3.72-11.07 Pa, n = 87) compared to the low DHA (0.7-3.62 Pa, n = 260, p = 0.01), as well at days with low Rdn (0.21-1.64, n = 229) compared to the high Rdn (1.65-7.2, n = 118, p = 0.03). A difference between DHA and Rdn effects on the emergency events related to different categories of circulatory diseases points to a higher sensitivity of rheumatic and cerebro-vascular diseases to DHA, and ischaemic and hypertensive diseases to Rdn. Results suggest that APF could be considered as a meteorotropic factor capable of influencing circulatory system diseases.
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Presión Atmosférica , Enfermedades Cardiovasculares/epidemiología , Interpretación Estadística de Datos , Servicios Médicos de Urgencia/estadística & datos numéricos , Periodicidad , Enfermedades Reumáticas/epidemiología , Medición de Riesgo/métodos , Bélgica/epidemiología , Monitoreo del Ambiente/estadística & datos numéricos , Monitoreo Epidemiológico , Humanos , Incidencia , Rayos Infrarrojos , Factores de Riesgo , Estaciones del Año , Estadística como AsuntoRESUMEN
Macular drusen are known to be a major risk factor of age-related macular degeneration (ARMD) of the retina. The use of laser coagulation of macular drusen to prevent the progression of a dystrophic process remains to be disputable question so far. This paper presents the clinical and functional results of laser coagulation of macular drusen in 30 patients with bilateral retinal ARMD. The routine ophthalmological study, photorecording, fluorescence angiography of the fundus of the eye, optic coherent tomography, and electrophysiological studies indicated macular drusen regression, increased visual acuity, and better electrophysiological parameters. Choriodal neovascularization and exudative complications did not develop in both the early and late follow-up periods.
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Coagulación con Láser/métodos , Retina/patología , Drusas Retinianas/cirugía , Agudeza Visual/fisiología , Anciano , Topografía de la Córnea , Electrorretinografía , Femenino , Angiografía con Fluoresceína , Estudios de Seguimiento , Fondo de Ojo , Humanos , Masculino , Persona de Mediana Edad , Retina/fisiopatología , Retina/cirugía , Drusas Retinianas/patología , Drusas Retinianas/fisiopatología , Tomografía de Coherencia Óptica , Resultado del TratamientoRESUMEN
Atmospheric pressure fluctuations (APF) might induce mechanical effects in the pars flaccida (PF) of the eardrum. To clarify these effects, different kinds of pressure oscillations (PO), chosen within the range of naturally occurring APF, were applied to the middle ears (ME) of gerbils. The linear displacement of the PF during a PO in the ME was measured by laser interferometry. The compliance of the PF to PO was calculated as the ratio of the amplitude of a PF oscillation to the amplitude of a PO. The displacement of the PF traced the PO in the entire range of frequencies (from 10mHz to 200mHz) and amplitudes (from 10Pa to 110Pa) applied to the ME. Moreover, the PF is found to be displaced by pressure pulses of a few pascals only using a PO with a complex shape. The differences found in the compliance of the PF due to PO with low (less than 20Pa) and high (more than 90Pa) amplitude point out that the mechanism of pressure regulation in the ME through the mechanical reaction of the PF in gerbil ears is better adapted to ordinary levels of natural APF than to extraordinary levels. The implications of these findings for the physiology of the human ME with respect to adaptation to natural APF are discussed.