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1.
Oper Dent ; 43(4): E166-E172, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29513639

RESUMEN

The aim of this study was to use ultrasonography to evaluate the effect of the self-assembling peptide P11-4 on acid erosion prevention. Curodont Repair (CR), which includes peptide P11-4, was used. Rectangular prisms of bovine enamel (4×1×1 mm) were immersed in pure orange juice for a period of 5 minutes six times per day for 28 days. These samples were divided into four groups of six specimens each and treated differently for an additional period of 28 days: 1) baseline group specimens were stored in artificial saliva; 2) CR group specimens were exposed to curodont without acid challenge; 3) NCRA (no curodont+acid challenge) specimens were treated with orange juice without curodont exposure; and 4) CRA (CR+acid challenge) specimens were treated with curodont before treatment with orange juice. The propagation time of longitudinal ultrasonic velocity (UV) was measured. Ultrastructural observation of each tested enamel surface was carried out using field-emission scanning electron microscopy (SEM). The UV data were analyzed using two-way analysis of variance with time and treatment as confounding factors. Post hoc pairwise tests among groups were performed using the Tukey honestly significant difference test. The average UV in intact bovine enamel for the baseline group ranged from 4,483 to 4,549 m/s and did not vary significantly within the test period. The average ultrasonic velocity (UV) in all samples decreased after the initial erosion. The UV in NCRA decreased further over time. Increased UVs were found for CR and CRA. For CR and CRA, there was no significant difference in UV at the end of the experiment from the initial value before erosion. In the results of SEM observation, the CR and CRA groups had similar morphologic features in that etching patterns were not clearly due to precipitation between the enamel rods. From the results of this in vitro study, it might be concluded that applying enamel matrix derivatives and self-assembling peptides on erosive lesions can improve remineralization.


Asunto(s)
Oligopéptidos/química , Erosión de los Dientes/prevención & control , Animales , Bovinos , Citrus/química , Técnicas In Vitro , Microscopía Electrónica de Rastreo , Saliva Artificial/química , Erosión de los Dientes/diagnóstico por imagen , Ultrasonografía/métodos
2.
Combust Flame ; 1712016.
Artículo en Inglés | MEDLINE | ID: mdl-30983597

RESUMEN

Phosphorus-containing compounds (PCCs) have been found to be significantly more effective than CF3Br for reducing burning velocity when added to stoichiometric hydrocarbon-air flames. However, when added to lean flames, DMMP (dimethylmethylphosphonate) is predicted to increase the burning velocity. The addition of DMMP to lean mixtures apparently increases the equivalence ratio (fuel/oxidizer) and the combustion temperature, as a result of hydrocarbon content of DMMP molecule. Premixed flames studies with added DMMP, OP(OH)3, and CF3Br are used to understand the different behavior with varying equivalence ratio and agent loading. Decrease of the equivalence ratio leads to the decrease of inhibition effectiveness of PCCs relative to bromine-containing compounds. For very lean mixtures CF3Br becomes more effective inhibitor than PCCs. Calculations of laminar burning velocities for pure DMMP/air mixtures predict the maximum burning velocity of 10.5 cm/s at 4.04 % of DMMP in air and at an initial temperature of 400 K. Adiabatic combustion temperature is 2155 K at these conditions.

3.
Braz J Biol ; 74(1): 111-23, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25055092

RESUMEN

The present study investigated the dynamic on a short-time scale in the vegetation in moist grassland of the Sete Cidades National Park, Piauí. Herb-subshrub layer samples was carried out in July 2007, 2009 and 2011. Changes in structural, floristic and functional traits in the community were assessed by species richness, diversity and similarity indices between those periods, as well as by hierarchical classification and ordination. Cluster and Principal Component Analyses identified functional groups according to 23 species trait state. To distinguish the contribution of space and time configuration in the community structure, we used the variance partition technique. The functional groups of chamaephytes and therophytes II were associated with wetter sites, while the groups of non-tussock hemicriptophytes I, tussock hemicriptophytes (FG4), and geophytes (FG5) were associated to the drier ones. We found a non-accelerated dynamics, at least on a short-time scale, represented by some descriptors in the community, such as the close similarity between the inventories and ordering of sampling transects in moist grassland. Therefore, besides considering the partition of the temporal niche as a mechanism for the co-existence of species, the heterogeneity of space dictated by environmental filters seems to determine the stability of the this grassland communities over time.


Asunto(s)
Biodiversidad , Poaceae/clasificación , Brasil , Dinámica Poblacional , Estaciones del Año , Especificidad de la Especie
4.
Ann Oncol ; 25(1): 251-7, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24356636

RESUMEN

BACKGROUND: Dose-dense weekly paclitaxel (Taxol) and carboplatin (dd-TC) improved survival compared with conventional tri-weekly paclitaxel and carboplatin (c-TC) as a first-line chemotherapy for newly diagnosed stage II-IV ovarian cancer in the Japanese Gynecologic Oncology Group 3016 trial. We report the quality-of-life (QoL) results from this trial. PATIENTS AND METHODS: A total of 637 patients were randomly assigned to receive c-TC or dd-TC (c-TC, n = 319; dd-TC, n = 312) and were asked to complete a QoL assessment at baseline, just after the third and sixth chemotherapy cycles, and at 12 months after randomization. QoL was assessed using Functional Assessment of Cancer Therapy (FACT)-general (FACT-G), FACT-taxane subscale (FACT-T), and FACT-ovary subscale (FACT-Ov). The overall QoL and that according to each subscale were analyzed using mixed-effects models adjusted for treatment and time. RESULTS: Baseline QoL assessment was completed by 204 out of 319 (63.9%) and 200 out of 312 (64.1%) patients in the c-TC and dd-TC groups, respectively. In these groups, the compliance rates with regard to QoL assessment were 74.5% and 73.0%, respectively, after three chemotherapy cycles; 86.8% and 86.9%, respectively, after six chemotherapy cycles; and 74.2% and 71.6%, respectively, at 12 months after randomization. The overall QoL did not differ significantly between the two treatment groups up to 12 months after randomization (P = 0.46). However, QoL according to the FACT-T subscale was significantly lower in the dd-TC group than in the c-TC group (P = 0.02). CONCLUSION: dd-TC does not decrease overall QoL compared with c-TC.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Quísticas, Mucinosas y Serosas/tratamiento farmacológico , Neoplasias Ováricas/tratamiento farmacológico , Calidad de Vida , Adulto , Anciano , Anciano de 80 o más Años , Carboplatino/administración & dosificación , Femenino , Humanos , Persona de Mediana Edad , Estadificación de Neoplasias , Neoplasias Quísticas, Mucinosas y Serosas/patología , Neoplasias Ováricas/patología , Paclitaxel/administración & dosificación , Encuestas y Cuestionarios , Resultado del Tratamiento
5.
Breast Cancer Res Treat ; 142(1): 69-80, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24122389

RESUMEN

This randomized, multicenter study compared the efficacy of docetaxel with or without capecitabine following fluorouracil/epirubicin/cyclophosphamide (FEC) therapy in operable breast cancer and investigated the role of Ki67 as a predictive biomarker. Patients were randomized to 4 cycles of docetaxel/capecitabine (docetaxel: 75 mg/m2 on day 1; capecitabine: 1,650 mg/m2 on days 1­14 every 3 weeks) or docetaxel alone (75 mg/m2 on day 1 every 3 weeks) after completion of 4 cycles of FEC (5-fluorouracil 500 mg/m2, epirubicin 100 mg/m2 and cyclophosphamide 500 mg/m2 on day 1 every 3 weeks). The primary endpoint was the pathological complete response (pCR) rate. Predictive factor analysis was conducted using clinicopathological markers, including hormone receptors and Ki67 labeling index (Ki67LI). A total of 477 patients were randomized; the overall response in the docetaxel/capecitabine and docetaxel groups was 88.3 and 87.4 %, respectively. There were no significant differences in the pCR rate (docetaxel/capecitabine: 23 %; docetaxel: 24 %; p = 0.748), disease-free survival, or overall survival. However, patients with mid-range Ki67LI (10­20 %) showed a trend towards improved pCR rate with docetaxel/capecitabine compared to docetaxel alone. Furthermore, multivariate logistic regression analysis showed pre-treatment Ki67LI (odds ratio 1.031; 95 % CI 1.014­1.048; p = 0.0004) to be a significant predictor of pCR in this neoadjuvant treatment setting. Docetaxel/capecitabine (after 4 cycles of FEC) did not generate significant improvement in pCR compared to docetaxel alone. However, exploratory analyses suggested that assessment of pre-treatment Ki67LI may be a useful tool in the identification of responders to preoperative docetaxel/capecitabine in early-stage breast cancer.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/patología , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Biomarcadores/metabolismo , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/mortalidad , Capecitabina , Ciclofosfamida , Desoxicitidina/administración & dosificación , Desoxicitidina/análogos & derivados , Docetaxel , Epirrubicina , Femenino , Fluorouracilo/administración & dosificación , Fluorouracilo/análogos & derivados , Humanos , Antígeno Ki-67/metabolismo , Persona de Mediana Edad , Terapia Neoadyuvante , Clasificación del Tumor , Estadificación de Neoplasias , Cuidados Preoperatorios , Pronóstico , Factores de Riesgo , Taxoides/administración & dosificación , Resultado del Tratamiento
6.
Braz J Biol ; 72(3 Suppl): 655-71, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23011296

RESUMEN

The Cerrado Domain comprises one of the most diverse savannas in the world and is undergoing a rapid loss of habitats due to changes in fire regimes and intense conversion of native areas to agriculture. We reviewed data on the biogeochemical functioning of Cerrado ecosystems and evaluated the potential impacts of regional climate changes. Variation in temperature extremes and in total amount of rainfall and altitude throughout the Cerrado determines marked differences in the composition of species. Cerrado ecosystems are controlled by interactions between water and nutrient availability. In general, nutrient cycles (N, P and base cations) are very conservative, while litter, microbial and plant biomass are important stocks. In terms of C cycling, root systems and especially the soil organic matter are the most important stocks. Typical cerrado ecosystems function as C sinks on an annual basis, although they work as source of C to the atmosphere close to the end of the dry season. Fire is an important factor altering stocks and fluxes of C and nutrients. Predicted changes in temperature, amount and distribution of precipitation vary according to Cerrado sub-regions with more marked changes in the northeastern part of the domain. Higher temperatures, decreases in rainfall with increase in length of the dry season could shift net ecosystem exchanges from C sink to source of C and might intensify burning, reducing nutrient stocks. Interactions between the heterogeneity in the composition and abundance of biological communities throughout the Cerrado Domain and current and future changes in land use make it difficult to project the impacts of future climate scenarios at different temporal and spatial scales and new modeling approaches are needed.


Asunto(s)
Carbono/metabolismo , Ecosistema , Nitrógeno/metabolismo , Suelo/química , Árboles/crecimiento & desarrollo , Biomasa , Brasil , Cambio Climático , Incendios , Estaciones del Año , Árboles/metabolismo , Agua
7.
Water Sci Technol ; 65(11): 2034-41, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22592475

RESUMEN

For practical applications of supercritical water oxidation to wastewater treatment, the deposition of inorganic salts in supercritical phase must be controlled to prevent a reactor from clogging. This study investigated enhanced removal of sodium salts with titanium particles, serving as a salt trapper and a catalyst precursor, and sodium recovery by sub-critical water. When Na(2)CO(3) was tested as a model salt, sodium removal efficiency was higher than theoretically maximum efficiency defined by Na(2)CO(3) solubility. The enhanced sodium removal resulted from in-situ synthesis of sodium titanate, which could catalyse acetic acid oxidation. The kinetics of sodium removal was described well by a diffusion mass-transfer model combined with a power law-type rate model of sodium titanate synthesis. Titanium particles showed positive effect on sodium removal in the case of NaOH, Na(2)SO(4) and Na(3)PO(4). However, they had negligible effect for NaCl and negative effect for Na(2)CrO(4), respectively. More than 99% of trapped sodium was recovered by sub-critical water except for Na(2)CrO(4). In contrast, sodium recovery efficiency remained less than 50% in the case of Na(2)CrO(4). Reused titanium particles showed the same performance for enhanced sodium removal. Enhanced salt removal supported by in-situ catalyst synthesis has great potential to enable both salt removal control and catalytic oxidation.


Asunto(s)
Sodio/química , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Agua/química , Catálisis , Microscopía Electrónica de Rastreo , Oxidación-Reducción , Óxidos/síntesis química , Titanio
8.
Reprod Domest Anim ; 47 Suppl 6: 43-6, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23279463

RESUMEN

As a step towards elucidation of the timing and mechanism of the determination of the number of ovulated ova in dogs, we excised one ovary 2, 5 and 8 days after the beginning of vulval bleeding and examined whether the lost ovulation function, assessed by estimating the number of ovulated oocytes, would be compensated for by the remaining ovary. The number of ovulated ova was maintained by the remaining ovary in the group that underwent unilateral ovariectomy 2 days after the beginning of vulval bleeding. However, in the groups ovariectomized 5 or 8 days after the beginning of vulval bleeding, no compensation for the number of ova that would have been ovulated from the lost ovary was observed; ova were ovulated only from the follicles 3 mm or greater in diameter observed in the remaining ovary at unilateral ovariectomy. Thus, in dogs, the number of ovulated ova is considered to be determined within 5 days after the beginning of vulval bleeding.


Asunto(s)
Perros/fisiología , Ovariectomía/veterinaria , Ovulación/fisiología , Animales , Femenino , Folículo Ovárico/fisiología
9.
Radiat Prot Dosimetry ; 147(1-2): 333-7, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21849327

RESUMEN

A web-based computed tomography (CT) dose calculation system (WAZA-ARI) is being developed based on the modern techniques for the radiation transport simulation and for software implementation. Dose coefficients were calculated in a voxel-type Japanese adult male phantom (JM phantom), using the Particle and Heavy Ion Transport code System. In the Monte Carlo simulation, the phantom was irradiated with a 5-mm-thick, fan-shaped photon beam rotating in a plane normal to the body axis. The dose coefficients were integrated into the system, which runs as Java servlets within Apache Tomcat. Output of WAZA-ARI for GE LightSpeed 16 was compared with the dose values calculated similarly using MIRD and ICRP Adult Male phantoms. There are some differences due to the phantom configuration, demonstrating the significance of the dose calculation with appropriate phantoms. While the dose coefficients are currently available only for limited CT scanner models and scanning options, WAZA-ARI will be a useful tool in clinical practice when development is finalised.


Asunto(s)
Carga Corporal (Radioterapia) , Método de Montecarlo , Dosis de Radiación , Radiometría/instrumentación , Tomografía Computarizada por Rayos X , Adulto , Humanos , Masculino , Fantasmas de Imagen , Efectividad Biológica Relativa
10.
Oncogene ; 30(27): 3084-95, 2011 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-21339742

RESUMEN

The B-cell translocation gene-2 (BTG2), a p53-inducible gene, is suppressed in mammary epithelial cells during gestation and lactation. In human breast cancer, decreased BTG2 expression correlates with high tumor grade and size, p53 status, blood and lymph vessel invasion, local and metastatic recurrence and decrease in overall survival, suggesting that suppression of BTG2 has a critical role in disease progression. To analyze the role of BTG2 in breast cancer progression, BTG2 expression was knocked down in mammary epithelial cells. Suppression of BTG2 enhances the motility of cells in vitro and tumor growth and metastasis in vivo. The effects of BTG2 knockdown are mediated through stabilization of the human epidermal growth factor receptor (HER) ligands neuregulin and epiregulin and activation of the HER2 and HER3 receptors, leading to elevated AKT phosphorylation. Suppression of HER activation using the tyrosine kinase inhibitor lapatinib abrogates the effects of BTG2 knockdown, including the increased cell migration observed in vitro and the enhancement of tumorigenesis and metastasis in vivo. These results link BTG2-dependent effects on tumor progression to ErbB receptor signaling, and raise the possibility that targeted inhibition of this pathway may be relevant in the treatment of breast cancers that have reduced BTG2 expression.


Asunto(s)
Neoplasias de la Mama/patología , Proteínas Inmediatas-Precoces/genética , Quinazolinas/uso terapéutico , Proteínas Supresoras de Tumor/genética , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Progresión de la Enfermedad , Femenino , Humanos , Lapatinib
11.
Radiat Prot Dosimetry ; 143(2-4): 450-4, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21183535

RESUMEN

Effects of structural materials in a wall-less tissue-equivalent proportional counter were evaluated based on the calculation of energy deposits by EGS5 and the measurement of lineal energy distributions using 290 MeV u(-1) carbon beams. It is found that the correction of measured data based on simulation is necessary for understanding the energy deposition spectra in the homogeneous condition in tissues.


Asunto(s)
Materiales Biomiméticos , Carbono , Iones Pesados , Monitoreo de Radiación/instrumentación , Diseño de Equipo , Análisis de Falla de Equipo , Dosis de Radiación
12.
Ann Oncol ; 22(3): 636-642, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20696677

RESUMEN

BACKGROUND: The purpose of this study is to assess the efficacy and safety of treatment with taxane plus platinum in combination therapies for advanced or recurrent endometrial carcinoma. PATIENTS AND METHODS: Patients with measurable disease derived from histologically confirmed stage III/IV or recurrent endometrial carcinoma were randomly assigned to receive docetaxel plus cisplatin (DP), docetaxel plus carboplatin (DC), or paclitaxel plus carboplatin (TC) every 3 weeks until disease progression or adverse events prohibited further therapy. Among these regimens, the study evaluated the tumor response rate as the primary end point as well as toxicity. RESULTS: Ninety patients were enrolled. Of them, 88 were eligible and consequently 29, 29, and 30 patients were randomly assigned to DP, DC, and TC, respectively. Tumor response rates were 51.7%, 48.3%, and 60.0% in DP, DC, and TC, respectively (P = 0.65). The following toxic effects were observed: grade 3/4 neutropenia in 83.3%, 90.0%, and 76.6%; febrile neutropenia in 10.0%, 6.7%, and 3.3%; grade 3/4 thrombocytopenia in 6.7%, 10.0%, and 10.0%; grade 3/4 diarrhea in 13.3%, 3.3%, and 0%, respectively; and grade 3 neurotoxicity in 10.0% of TC. These toxicity profiles were not significantly different. CONCLUSION: The taxane plus platinum combination therapies could be candidates in further phase III trials for endometrial carcinoma.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Carcinoma/tratamiento farmacológico , Neoplasias Endometriales/tratamiento farmacológico , Recurrencia Local de Neoplasia/tratamiento farmacológico , Adulto , Anciano , Carboplatino/administración & dosificación , Carboplatino/efectos adversos , Carcinoma/patología , Cisplatino/administración & dosificación , Cisplatino/efectos adversos , Docetaxel , Neoplasias Endometriales/patología , Femenino , Humanos , Estimación de Kaplan-Meier , Persona de Mediana Edad , Estadificación de Neoplasias , Paclitaxel/administración & dosificación , Paclitaxel/efectos adversos , Taxoides/administración & dosificación , Taxoides/efectos adversos , Resultado del Tratamiento
13.
Oncogene ; 29(13): 1941-51, 2010 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-20101228

RESUMEN

Malignant pleural mesothelioma (MPM) is resistant to chemotherapy and thus shows a dismal prognosis. Osteopontin (OPN), a secreted noncollagenous and phosphoprotein, is suggested to be involved in the pathogenesis of MPM. However, the precise role of OPN, especially in the multidrug resistance of MPM, remains to be elucidated. We therefore established stable transfectants (ACC-MESO-1/OPN), which constitutively express OPN, to determine its role in the chemoresistance observed in MPM. The introduction of the OPN gene provides MPM cells with upregulated multidrug resistance through the mechanism of enhanced hyaluronate (HA) binding. The expression of CD44 variant isoforms, which inhibit HA binding, significantly decreased in ACC-MESO-1/OPN cells in comparison to control transfectants. Interestingly, the inhibition of the HA-CD44 interaction abrogated multidrug resistance in the ACC-MESO-1/OPN, thus suggesting the involvement of the surviving signal emanating from the HA-CD44 interaction. An enhanced level of the p-Akt in ACC-MESO-1/OPN cells was observed, and was diminished by CD44 siRNA. Inhibition of the Akt phosphorylation increased in number of the cells underwent apoptosis induced by NVB, VP-16 and GEM. Collectively, these results indicate that OPN is strongly involved in multidrug resistance by enhancing the CD44 binding to HA.


Asunto(s)
Antineoplásicos/farmacología , Resistencia a Múltiples Medicamentos/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Ácido Hialurónico/farmacología , Mesotelioma/patología , Osteopontina/metabolismo , Neoplasias Pleurales/patología , Adhesión Celular/efectos de los fármacos , Línea Celular Tumoral , Etopósido/farmacología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Ácido Hialurónico/metabolismo , Mesotelioma/metabolismo , Neoplasias Pleurales/metabolismo , ARN Interferente Pequeño/farmacología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética
14.
Reprod Domest Anim ; 44 Suppl 2: 230-3, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19754575

RESUMEN

The fertile period for natural mating in dogs extends from before ovulation until day 5 post ovulation (PO) and involves a delay in oocyte maturation until 2-3 days PO and viability of secondary oocytes for 48-60 h or more. Spermatozoa do not enter the uterus after vaginal insemination in late oestrus. Cervical closure appears to occur on average 5 days PO, but conception may occur following intrauterine artificial insemination (IUAI) up to 8 days PO. Therefore, the present study was conducted to clarify the duration of fertility of canine ova. Using IUAI at 6, 7, 8 and 9 days PO (n = 5 bitches each) conception rates were 100%, 71.4%, 37.5% and 0%, respectively, with an average litter resorption rate of 30.8%, and with mean litter sizes and times to delivery PO being 4.3 +/- 1.6 and 64.3 +/- 0.3 days, 4.0 +/- 1.4 and 66.3 +/- 0.4 days, and 2.5 and 68 days for IUAI at 6, 7 and 8 days, respectively. The high pregnancy rates with IUAI at 6 and 7 days PO confirm that many canine oocytes are fertile at 4-5 days after maturation. The high rate of resorption was presumably because of aging of ova or asynchrony between embryonic development and the intrauterine environment.


Asunto(s)
Perros/fisiología , Óvulo/fisiología , Preñez , Animales , Femenino , Fertilización , Inseminación Artificial/veterinaria , Embarazo , Factores de Tiempo
15.
Radiat Prot Dosimetry ; 133(1): 35-43, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19181661

RESUMEN

A system has been developed to assess radiation dose distribution inside the body of exposed persons in a radiological accident by utilising radiation transport calculation codes-MCNP and MCNPX. The system consists mainly of two parts, pre-processor and post-processor of the radiation transport calculation. Programs for the pre-processor are used to set up a 'problem-dependent' input file, which defines the accident condition and dosimetric quantities to be estimated. The program developed for the post-processor part can effectively indicate dose information based upon the output file of the code. All of the programs in the dosimetry system can be executed with a generally used personal computer and accurately give the dose profile to an exposed person in a radiological accident without complicated procedures. An experiment using a physical phantom was carried out to verify the availability of the dosimetry system with the developed programs in a gamma ray irradiation field.


Asunto(s)
Servicios Médicos de Urgencia/métodos , Exposición a Riesgos Ambientales/análisis , Protección Radiológica/métodos , Liberación de Radiactividad Peligrosa , Medición de Riesgo/métodos , Programas Informáticos , Humanos , Método de Montecarlo , Reproducibilidad de los Resultados , Factores de Riesgo , Sensibilidad y Especificidad
16.
Radiat Prot Dosimetry ; 126(1-4): 595-9, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17510203

RESUMEN

A system utilising radiation transport codes has been developed to derive accurate dose distributions in a human body for radiological accidents. A suitable model is quite essential for a numerical analysis. Therefore, two tools were developed to setup a 'problem-dependent' input file, defining a radiation source and an exposed person to simulate the radiation transport in an accident with the Monte Carlo calculation codes-MCNP and MCNPX. Necessary resources are defined by a dialogue method with a generally used personal computer for both the tools. The tools prepare human body and source models described in the input file format of the employed Monte Carlo codes. The tools were validated for dose assessment in comparison with a past criticality accident and a hypothesized exposure.


Asunto(s)
Modelos Biológicos , Método de Montecarlo , Neutrones , Exposición Profesional/análisis , Monitoreo de Radiación/métodos , Protección Radiológica/métodos , Liberación de Radiactividad Peligrosa , Medición de Riesgo/métodos , Simulación por Computador , Diseño de Equipo , Análisis de Falla de Equipo , Humanos , Dosis de Radiación , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
18.
Mol Biol (Mosk) ; 38(2): 276-87, 2004.
Artículo en Ruso | MEDLINE | ID: mdl-15125233

RESUMEN

RNA interference (RNAi) may be induced by a plasmid with an inverted repeat (IR) sequence directing transcription of hairpin-type double-stranded RNA (dsRNA). This study examines the effects of changing various parameters of IR constructs on Drosophila and mammalian RNAi, using the dual luciferase system, RNAi activity was found to vary depending on IR length ass well as the length and sequence of the internal loop separating sense and antisense sequences. Both transient and stable RNAi occurred in Drosophila cultured cells. Although transient DNA-mediated RNAi was noted in most mammalian cells, no mammalian cells stably possessing IR sequences and hence RNAi activity could be obtained. In Drosophila, DNA-mediated RNAi was considerably weaker than long-dsRNA-mediated RNAi. The cytological data indicated that this was most probably caused by abortive processing of hairpin RNA produced within cells. DNA-mediated RNAi was examined at the level of Drosophila individuals using extramacrochaetae as a model gene, and the presence of an intron sequence in the single-stranded loop region was shown to be essential for effective RNAi.


Asunto(s)
Interferencia de ARN , ARN Bicatenario/genética , Animales , Secuencia de Bases , Línea Celular , ADN/genética , Cartilla de ADN , Drosophila , Humanos , Hibridación in Situ , Plásmidos , Regiones Promotoras Genéticas , ARN Bicatenario/biosíntesis
19.
Radiat Prot Dosimetry ; 106(3): 197-206, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-14690320

RESUMEN

Some data were derived using recent sophisticated methods to rapidly convert specific activity of induced 24Na to average dose over a whole body in criticality accidents. Monte Carlo calculations using the MCNP-4B code were performed to study energy spectra of neutrons and gamma rays for some criticality systems with fissile uranium. Absorbed dose to the human body and the activation of sodium were also analysed against external radiation by simulations using a MIRD-5 type phantom and the calculated energy spectra. It was found that the neutron dose assessment from induced 24Na would be important to give medical staff initial guidance for treatment of a victim. However, the energy distribution of incident neutrons to the human body did not significantly influence the conversion from the specific activity of 24Na to dose from gamma rays induced within a body. Analyses were made to clarify the dependence of conversion from 24Na specific activity to neutron dose on the orientation toward the source and the size of the human body. The total dose estimated based upon the obtained data ranged from 33 mGy to 514 mGy for a given specific activity of 1.4 kBq 24Na per g 23Na for some criticality assemblies. This study suggested that the size of uranium solution and material around the fuel should be defined to properly estimate the total dose, including the dose from external photons.


Asunto(s)
Radiometría/métodos , Sodio , Relación Dosis-Respuesta en la Radiación , Rayos gamma , Humanos , Método de Montecarlo , Neutrones , Fantasmas de Imagen , Fotones , Dosis de Radiación
20.
Radiat Prot Dosimetry ; 103(2): 125-30, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12593431

RESUMEN

Absorbed dose to tooth enamel was examined against external photon exposure by measurements with thermoluminescence dosemeters (TLDs) and Monte Carlo calculations. TLDs were placed in a realistic physical phantom to measure dose to the teeth region in a head. A voxel-type phantom was constructed from computed tomography (CT) images of the physical phantom. Monte Carlo calculations with this voxel-type phantom were performed to analyse the results of the experiments. The data obtained were compared to the enamel doses, which were calculated with a modified MIRD-type phantom and already given in a previous paper. It was confirmed that the data derived with the MIRD-type phantom are applicable for retrospective individual dose assessments by electron spin resonance (ESR) dosimetry using teeth for the photon energy region above 300 keV. The analysis, however, indicated that the configuration of the head can affect the enamel dose relative to external exposure to photons with energy below 100 keV.


Asunto(s)
Esmalte Dental/efectos de la radiación , Rayos gamma , Dosimetría Termoluminiscente/métodos , Calibración , Radioisótopos de Cesio , Radioisótopos de Cobalto , Relación Dosis-Respuesta en la Radiación , Espectroscopía de Resonancia por Spin del Electrón , Diseño de Equipo , Humanos , Masculino , Método de Montecarlo , Fantasmas de Imagen , Poliuretanos , Dosis de Radiación , Cráneo , Dosimetría Termoluminiscente/instrumentación , Tomografía Computarizada por Rayos X
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