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1.
Br Poult Sci ; 64(1): 47-55, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36129068

RESUMO

1. This study assessed 1) the effects of Paracoccus carotinifaciens supplementation containing high astaxanthin levels on egg production performance and quality, 2) dynamics of carotenoids levels in the egg yolk and 3) taste of astaxanthin-rich egg yolk.2. Laying hens were fed diets containing different levels of P. carotinifaciens-derived astaxanthin (ASX; 0, 2, 4, 8, or 16 ppm) for 28 d (experiment 1) or a diet containing 16 ppm astaxanthin for 28 d followed by a 0 ppm astaxanthin diet for 28 days (experiment 2).3. Production performance, egg quality and egg yolk carotenoid levels were examined in experiment 1 (Ex1) and the dynamics of egg yolk carotenoid levels and egg yolk taste in experiment 2 (Ex2).4. ASX supplementation did not affect production performance or egg quality. ASX levels in the egg yolk became saturated after seven days of 16 ppm supplementation and decreased to less than one-tenth of the saturated levels seven days after supplementation cessation. Supplementation with 16 ppm ASX for 28 d did not affect egg yolk taste.5. Supplementation resulted in the production of ASX-rich eggs for a brief period without affecting production performance, egg quality or taste. Understanding the time taken for the incorporation of ASX into egg yolks is beneficial for value-added egg production and may help in minimising supplementation costs.


Assuntos
Galinhas , Óvulo , Feminino , Animais , Gema de Ovo , Dieta/veterinária , Carotenoides , Suplementos Nutricionais/análise , Ração Animal/análise , Ovos/análise
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2021: 6814-6817, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34892672

RESUMO

This paper describes the development of a human electrical phantom in the low-frequency band. Conventional high-hydrous gel phantoms cannot mimic the electrical properties of the human body in the low-frequency band. Titanium oxide coated with antimony-doped tin oxide (ATO/TiO2) was added to the high-hydrous gel phantom, and the electrical properties were evaluated in terms of the amount of material added. The developed phantom had an error of less than 10% in the range of 100 kHz to 1 MHz, which conforms with the electrical properties of human muscles. Particularly, at 125 kHz, the error was 2.71% and 4.35% for relative permittivity and conductivity, respectively. The variation in the electrical properties of the developed phantom was evaluated, and it was confirmed that sufficient reproducibility could be obtained.


Assuntos
Eletricidade , Condutividade Elétrica , Humanos , Imagens de Fantasmas , Reprodutibilidade dos Testes , Titânio
3.
Proc Natl Acad Sci U S A ; 118(8)2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33608462

RESUMO

Nonreciprocity emerges in nature and in artificial objects from various physical origins, being widely utilized in contemporary technologies as exemplified by diode elements in electronics. While most of the nonreciprocal phenomena are realized by employing interfaces where the inversion symmetry is trivially lifted, nonreciprocal transport of photons, electrons, magnons, and possibly phonons also emerge in bulk crystals with broken space inversion and time reversal symmetries. Among them, directional propagation of bulk magnons (i.e., quanta of spin wave excitation) is attracting much attention nowadays for its potentially large nonreciprocity suitable for spintronic and spin-caloritronic applications. Here, we demonstrate nonreciprocal propagation of spin waves for the conical spin helix state in Cu2OSeO3 due to a combination of dipole and Dzyaloshinskii-Moriya interactions. The observed nonreciprocal spin dispersion smoothly connects to the hitherto known magnetochiral nonreciprocity in the field-induced collinear spin state; thus, all the spin phases show diode characteristics in this chiral insulator.

4.
Biochem Biophys Res Commun ; 534: 702-706, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33199025

RESUMO

There have been several clinical reports of transient postoperative hyperglycemia in patients with insulinoma, but the effect of insulinoma on normal ß-cells has not been investigated. We examined the glucose transporter 2 (GLUT2) and glucagon-like peptide 1 receptor (GLP1R) expression in normal pancreatic ß-cells of five patients with insulinoma and five patients with normal glucose tolerance (NGT) as controls. The positive rate of GLUT2-or GLP1R-positive islets in the nontumor area was calculated by the ratio with the analyzed islets. For functional in vitro analyses, q-PCR and Western blotting were performed after insulin loading on MIN6 cells. The expression rates of both GLUT2 and GLP1R were significantly lower in nontumor area islets of insulinoma patients than in patients with NGT (GLUT2: 31.6 ± 15.3% vs 95.9 ± 6.7%, p < 0.01, GLP1R: 66.8 ± 15.0% vs 96.7 ± 5.0%, p < 0.01). Exposure of MIN6 cells to high concentrations of insulin resulted in a significant decrease in GLUT2 protein for 12 h and GLP1R protein for 24 h (GLUT2; 1.00 ± 0.079 vs 0.81 ± 0.04. p = 0.02, GLP1R; 1.00 ± 0.10 vs 0.50 ± 0.24, p = 0.03) but not in those mRNAs. Our findings show that insulinoma is associated with the downregulation of GLUT2 and GLP1R expression in nontumor area islets. These phenomena may be caused by high levels of insulin.


Assuntos
Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Transportador de Glucose Tipo 2/metabolismo , Hiperinsulinismo/etiologia , Insulinoma/cirurgia , Neoplasias Pancreáticas/cirurgia , Idoso , Animais , Linhagem Celular , Feminino , Receptor do Peptídeo Semelhante ao Glucagon 1/genética , Transportador de Glucose Tipo 2/genética , Humanos , Insulina/farmacologia , Secreção de Insulina , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Insulinoma/metabolismo , Masculino , Camundongos , Pessoa de Meia-Idade , Neoplasias Pancreáticas/metabolismo , Período Pós-Operatório
5.
Phys Rev Lett ; 123(7): 077401, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31491127

RESUMO

In magnetoelectric materials, where the time-reversal and space-inversion symmetries are simultaneously broken, optical properties can differ between the opposite propagation directions of light. We report on an experimental observation of nonreciprocal trajectory of a light ray in magnetoelectric material CuB_{2}O_{4}. The light is refracted in different ways between the opposite propagation directions of light. We find a nonreciprocal refraction at the interface between a matter with macroscopic toroidal moment and vacuum. The resultant nonreciprocal deflection of the light is 0.005 deg, which is quantitatively explained using Fermat's principle.

6.
Epidemiol Infect ; 145(14): 2896-2911, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28826420

RESUMO

The purpose of this study was to clarify the association between hand, foot, and mouth disease (HFMD) epidemics and meteorological conditions. We used HFMD surveillance data of all 47 prefectures in Japan from January 2000 to December 2015. Spectral analysis was performed using the maximum entropy method (MEM) for temperature-, relative humidity-, and total rainfall-dependent incidence data. Using MEM-estimated periods, long-term oscillatory trends were calculated using the least squares fitting (LSF) method. The temperature and relative humidity thresholds of HFMD data were estimated from the LSF curves. The average temperature data indicated a lower threshold at 12 °C and a higher threshold at 30 °C for risk of HFMD infection. Maximum and minimum temperature data indicated a lower threshold at 6 °C and a higher threshold at 35 °C, suggesting a need for HFMD control measures at temperatures between 6 and 35 °C. Based on our findings, we recommend the use of maximum and minimum temperatures rather than the average temperature, to estimate the temperature threshold of HFMD infections. The results obtained might aid in the prediction of epidemics and preparation for the effect of climatic changes on HFMD epidemiology.


Assuntos
Epidemias , Doença de Mão, Pé e Boca/epidemiologia , Umidade , Chuva , Temperatura , Criança , Pré-Escolar , Doença de Mão, Pé e Boca/virologia , Humanos , Incidência , Lactente , Recém-Nascido , Japão/epidemiologia , Análise dos Mínimos Quadrados , Estações do Ano
7.
Appl Radiat Isot ; 120: 30-39, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27898372

RESUMO

This study analyzes the Thermoluminescence (TL) emissions for five emission bands, trace element concentrations and defects in quartz grains extracted from metamorphic rocks and quartz veins in the Sambagawa metamorphic belt, central Shikoku. An emission of 500nm with 195, 245, and 320-325°C glow peaks are observed through the lowest to highest grade samples. A 450nm emission band with intense 195 and 245°C glow peaks and a 320-325°C shoulder peak is found in the higher grade samples. A 570nm emission band with a 170°C glow peak is observed in the samples derived from the lower grade zones. These characteristics of TL emissions of quartz suggest that they can be an indicator for the identification of rock derived from different metamorphic grades. The higher metamorphic grade samples with 450nm emission bands in particular show higher intensities of the E1' center. This relation indicates that the activation of the E1' center in higher metamorphic conditions possibly contributed to the 450nm emission band. Also, the 500nm emission band is generally observed in the samples with the signal intensities of the Aluminum hole center, suggesting that the center is the source of this emission band. We also observed that the lower metamorphic grade samples contain lower signal intensities of the Aluminum hole center, despite higher aluminum concentrations. This inconsistency indicates that the formation of interstitial aluminum ions cause local lattice distortion regions, where self-trapped excitons can be formed and presumably provide the 570nm emissions.

8.
Prostate Cancer Prostatic Dis ; 19(1): 57-62, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26503109

RESUMO

BACKGROUND: We prospectively examined influence of androgen deprivation therapy (ADT) on lipid and glucose metabolisms in Japanese patients with prostate cancer. METHODS: Patients with prostate cancer who were hormone-naive and scheduled to receive long-term ADT were recruited between 2011 and 2013. Body weight, abdominal circumference and blood testing associated with lipid and glucose metabolism were recorded every 3 months during 1 year of ADT. Computed tomography (CT) was performed to measure areas of subcutaneous and visceral fat before and after 1 year of ADT. ADT was limited to a luteinizing hormone-releasing hormone (LHRH) agonist with or without bicalutamide. RESULTS: Of 218 patients registered, data were available from 177 patients who completed 1 year of ADT. Of these, CT was performed before and after 1 year of ADT in 88 patients. Median age was 75 years (range, 49-85 years). Median PSA before ADT was 16.7 ng ml(-1) (range, 0.3-3316). Clinical stage was B (54.2%), C (23.2%) and D (20.9%). Mean increases in body weight and abdominal circumference after 1 year of ADT were 2.9 and 3.0%, respectively. Mean increases in total, low-density lipoprotein and high-density lipoprotein cholesterol and triglycerides were 10.6, 14.3, 7.8 and 16.2%, respectively. Mean increases in fasting blood sugar and hemoglobin A1c (HbA1c) were 3.9 and 2.7%, respectively. Lipid alterations were noted in patients without comorbidities, whereas changes in HbA1c were noted in patients with diabetes mellitus at baseline. These lipid and glucose alterations were prominent in the early ADT period. Both visceral and subcutaneous fat, as measured by CT, increased by >20%. The increase in subcutaneous fat was significantly greater than that in visceral fat (P=0.028). CONCLUSIONS: One year of ADT significantly changed lipid and glucose metabolism in Japanese patients with prostate cancer. Patient characteristics or comorbidities at baseline may be associated with ADT-induced metabolic changes.


Assuntos
Antagonistas de Androgênios/administração & dosagem , Diabetes Mellitus/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Antagonistas de Androgênios/metabolismo , Diabetes Mellitus/patologia , Glucose/metabolismo , Hemoglobinas Glicadas/metabolismo , Humanos , Gordura Intra-Abdominal/efeitos dos fármacos , Japão , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia
9.
Phys Rev Lett ; 115(26): 267207, 2015 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-26765023

RESUMO

We experimentally demonstrate one-way transparency of light in multiferroic CuB(2)O(4). The material is rendered transparent for light propagating in one direction, while opaque for light propagating in the opposite direction. The novel transparency results from a destructive interference of the electric dipole and magnetic dipole transitions. The realization of the effect has been accomplished by the application of a high magnetic field and the proper selection of the propagation direction of light in agreement with our quantum mechanical formulation of nonreciprocal directional dichroism.

10.
J Obstet Gynaecol ; 35(1): 69-73, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25020206

RESUMO

Ovarian and endometrial cancers diagnosed at advanced stages are often associated with malignant ascites. This study aimed to determine the safety, feasibility and efficacy of intraperitoneal (IP) docetaxel (TXT) for the treatment of ascites. A phase I study, including nine patients, was undertaken to determine the maximum tolerable dose. Efficacy was retrospectively assessed in 18 patients treated with 40-70 mg/m(2) IP TXT between 2005 and 2012. In a phase I study, the dose was safely escalated to a maximum of 70 mg/m(2), at which level no patients had grade -3 haematological adverse events. In a retrospective study of 18 patients, seven had an Eastern Cooperative Oncology Group performance status of 3; 16 had prior paclitaxel administration and two, with doses of 40 and 70 mg/m(2), experienced a serological response and a decrease in paracentesis. Thus, palliative treatment of recurrent OC should be further studied with 40 mg/m(2) among more patients, and 70 mg/m(2) could be evaluated for first-line IP chemotherapy.


Assuntos
Adenocarcinoma de Células Claras/tratamento farmacológico , Antineoplásicos/administração & dosagem , Ascite/tratamento farmacológico , Neoplasias dos Genitais Femininos/tratamento farmacológico , Taxoides/administração & dosagem , Adenocarcinoma de Células Claras/complicações , Idoso , Ascite/etiologia , Docetaxel , Estudos de Viabilidade , Feminino , Neoplasias dos Genitais Femininos/complicações , Humanos , Infusões Parenterais , Pessoa de Meia-Idade , Estudos Retrospectivos , Terapia de Salvação
11.
Water Res ; 47(19): 7078-86, 2013 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-24200002

RESUMO

Emission of nitrous oxide (N2O) during biological wastewater treatment is of growing concern since N2O is a major stratospheric ozone-depleting substance and an important greenhouse gas. The emission of N2O from a lab-scale granular sequencing batch reactor (SBR) for partial nitrification (PN) treating synthetic wastewater without organic carbon was therefore determined in this study, because PN process is known to produce more N2O than conventional nitrification processes. The average N2O emission rate from the SBR was 0.32 ± 0.17 mg-N L(-1) h(-1), corresponding to the average emission of N2O of 0.8 ± 0.4% of the incoming nitrogen load (1.5 ± 0.8% of the converted NH4(+)). Analysis of dynamic concentration profiles during one cycle of the SBR operation demonstrated that N2O concentration in off-gas was the highest just after starting aeration whereas N2O concentration in effluent was gradually increased in the initial 40 min of the aeration period and was decreased thereafter. Isotopomer analysis was conducted to identify the main N2O production pathway in the reactor during one cycle. The hydroxylamine (NH2OH) oxidation pathway accounted for 65% of the total N2O production in the initial phase during one cycle, whereas contribution of the NO2(-) reduction pathway to N2O production was comparable with that of the NH2OH oxidation pathway in the latter phase. In addition, spatial distributions of bacteria and their activities in single microbial granules taken from the reactor were determined with microsensors and by in situ hybridization. Partial nitrification occurred mainly in the oxic surface layer of the granules and ammonia-oxidizing bacteria were abundant in this layer. N2O production was also found mainly in the oxic surface layer. Based on these results, although N2O was produced mainly via NH2OH oxidation pathway in the autotrophic partial nitrification reactor, N2O production mechanisms were complex and could involve multiple N2O production pathways.


Assuntos
Reatores Biológicos/microbiologia , Consórcios Microbianos/genética , Óxido Nitroso/análise , Óxido Nitroso/metabolismo , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Amônia/metabolismo , Processos Autotróficos , Concentração de Íons de Hidrogênio , Hidroxilamina/metabolismo , Hibridização in Situ Fluorescente , Nitrificação , Eliminação de Resíduos Líquidos/instrumentação
12.
Rev Sci Instrum ; 82(11): 113701, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22128978

RESUMO

In order to achieve nondestructive observation of the three-dimensional spatially resolved electronic structure of solids, we have developed a scanning photoelectron microscope system with the capability of depth profiling in electron spectroscopy for chemical analysis (ESCA). We call this system 3D nano-ESCA. For focusing the x-ray, a Fresnel zone plate with a diameter of 200 µm and an outermost zone width of 35 nm is used. In order to obtain the angular dependence of the photoelectron spectra for the depth-profile analysis without rotating the sample, we adopted a modified VG Scienta R3000 analyzer with an acceptance angle of 60° as a high-resolution angle-resolved electron spectrometer. The system has been installed at the University-of-Tokyo Materials Science Outstation beamline, BL07LSU, at SPring-8. From the results of the line-scan profiles of the poly-Si/high-k gate patterns, we achieved a total spatial resolution better than 70 nm. The capability of our system for pinpoint depth-profile analysis and high-resolution chemical state analysis is demonstrated.


Assuntos
Elétrons , Microscopia Eletrônica de Varredura/instrumentação , Nanotecnologia/instrumentação , Análise Espectral/instrumentação
13.
J Clin Pharm Ther ; 36(1): 103-10, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21198725

RESUMO

WHAT IS KNOWN AND OBJECTIVE: Telmisartan, an angiotensin II type 1 receptor blocker (ARB), acts as a partial agonist for peroxisome proliferator-activated receptor-γ, and thus improves abnormalities of glucose metabolism and hypertriglyceridaemia in addition to its documented blood pressure-lowering effects. Recently, it has been demonstrated that telmisartan also lowers the levels of total cholesterol and low-density lipoprotein (LDL) cholesterol levels. This study was designed to investigate the mechanism of cholesterol reduction. METHODS: We measured serum levels of cholestanol, a cholesterol absorption marker, and lathosterol, a cholesterol synthesis marker, in 20 patients with both hypercholesterolaemia and hypertension. Ten patients were treated with telmisartan and the remaining 10 with fluvastatin. RESULTS: After 3 months of treatment, total and LDL cholesterol levels decreased in the telmisartan group (P<0.01 for both total and LDL cholesterol levels) and the fluvastatin group (P<0.001 for both total and LDL cholesterol levels). The change in cholestanol level after 3 months of treatment was positively correlated with the levels of total (R=0.72, P<0.05) and LDL cholesterol (R=0.81, P<0.01) in the telmisartan group. The change in lathosterol level was positively correlated with the levels of total (R=0.88, P=0.001) and LDL cholesterol (R=0.89, P=0.001) in the fluvastatin group. WHAT IS NEW AND CONCLUSIONS: Our results suggest that the cholesterol-lowering effect of telmisartan might be caused by inhibition of cholesterol absorption, whereas that of statins is by inhibition of cholesterol synthesis. If confirmed, co-treatment with the two agents may be useful for synergistically lowering cholesterol in hypertensive patients.


Assuntos
Anticolesterolemiantes/uso terapêutico , Benzimidazóis/uso terapêutico , Benzoatos/uso terapêutico , Colesterol/sangue , Hipercolesterolemia/tratamento farmacológico , Absorção Intestinal/efeitos dos fármacos , Idoso , Idoso de 80 Anos ou mais , Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Anticolesterolemiantes/farmacologia , Benzimidazóis/farmacologia , Benzoatos/farmacologia , Biomarcadores/sangue , Colestanol/sangue , Colesterol/metabolismo , LDL-Colesterol/sangue , Ácidos Graxos Monoinsaturados/farmacologia , Ácidos Graxos Monoinsaturados/uso terapêutico , Feminino , Fluvastatina , Fármacos Gastrointestinais/farmacologia , Fármacos Gastrointestinais/uso terapêutico , Humanos , Hipercolesterolemia/sangue , Hipercolesterolemia/complicações , Hipertensão/sangue , Hipertensão/complicações , Hipertensão/tratamento farmacológico , Indóis/farmacologia , Indóis/uso terapêutico , Masculino , Pessoa de Meia-Idade , PPAR gama/agonistas , Telmisartan
14.
Rapid Commun Mass Spectrom ; 24(9): 1281-6, 2010 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-20391599

RESUMO

Evaluation of the openness of the nitrogen (N) cycle in forest ecosystems is important in efforts to improve forest management because the N supply often limits primary production. The use of the oxygen isotope ratio (delta(18)O) of nitrate is a promising approach to determine how effectively atmospheric nitrate can be retained in a forest ecosystem. We investigated the delta(18)O of nitrate in stream water in order to estimate the contribution of atmospheric NO(3) (-) in stream-water NO(3) (-) (f(atm)) from 26 watersheds with different stand ages (1-87 years) in Japan. The stream-water nitrate concentrations were high in young forests whereas, in contrast, old forests discharged low-nitrate stream water. These results implied a low f(atm) and a closed N cycle in older forests. However, the delta(18)O values of nitrate in stream water revealed that f(atm) values were higher in older forests than in younger forests. These results indicated that even in old forests, where the discharged N loss was small, atmospheric nitrate was not retained effectively. The steep slopes of the studied watersheds (>40 degrees ) which hinder the capturing of atmospheric nitrate by plants and microbes might be responsible for the inefficient utilization of atmospheric nitrate. Moreover, the unprocessed fraction of atmospheric nitrate in the stream-water nitrate in the forest (f(unprocessed)) was high in the young forest (78%), although f(unprocessed) was stable and low for other forests (5-13%). This high f(unprocessed) of the young forest indicated that the young forest retained neither atmospheric NO(3) (-) nor soil NO(3) (-) effectively, engendering high stream-water NO(3) (-) concentrations.


Assuntos
Nitratos/análise , Isótopos de Nitrogênio/análise , Isótopos de Oxigênio/análise , Chuva/química , Rios/química , Traqueófitas , Árvores , Cromatografia Gasosa-Espectrometria de Massas , Geografia , Japão , Sensibilidade e Especificidade
15.
Eur J Neurol ; 15(3): 295-300, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18290851

RESUMO

We created an algorithm for diagnosing subtypes of cerebral infarction (CI) during the acute stage by combining atrial fibrillation (AF) and D-dimer levels. One-hundred and eight patients hospitalized for acute CI were retrospectively analyzed. CI was classified into cardioembolic, atherothrombotic, lacunar infarction or others. Patients were classified in AF group if they had AF on admission or a prior history of AF. This group was diagnosed to suffer cardioembolic infarction. In non-AF group, cardioembolic infarction was diagnosed when D-dimer level exceeded the cutoff point determined using a receiver operating curve. Then, usefulness of the algorithm was validated prospectively in 259 consecutive patients with acute CI. For the retrospective group, cardioembolic infarction was found in 82% of the AF group. In non-AF group, cardioembolic infarction was found in only 2%, when D-dimer level was <1.6 microg/ml. However, 41% of non-AF group with atherothrombotic infarction had elevated D-dimer level (> or =1.6 microg/ml). Results for the validation group were similar to those for the retrospective group (sensitivity, 89%; specificity, 66%; positive predictive value, 50%; and negative predictive value, 94%). D-dimer level in combination with AF can be useful for distinguishing CI subtypes during the acute stage.


Assuntos
Algoritmos , Fibrilação Atrial , Infarto Cerebral/diagnóstico , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Idoso , Idoso de 80 Anos ou mais , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Reprodutibilidade dos Testes , Estudos Retrospectivos
16.
Radiat Prot Dosimetry ; 120(1-4): 176-83, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16702247

RESUMO

The objective of the Third International Intercomparison on EPR Tooth Dosimetry was to evaluate laboratories performing tooth enamel dosimetry <300 mGy. Final analysis of results included a correlation analysis between features of laboratory dose reconstruction protocols and dosimetry performance. Applicability of electron paramagnetic resonance (EPR) tooth dosimetry at low dose was shown at two applied dose levels of 79 and 176 mGy. Most (9 of 12) laboratories reported the dose to be within 50 mGy of the delivered dose of 79 mGy, and 10 of 12 laboratories reported the dose to be within 100 mGy of the delivered dose of 176 mGy. At the high-dose tested (704 mGy) agreement within 25% of the delivered dose was found in 10 laboratories. Features of EPR dose reconstruction protocols that affect dosimetry performance were found to be magnetic field modulation amplitude in EPR spectrum recording, EPR signal model in spectrum deconvolution and duration of latency period for tooth enamel samples after preparation.


Assuntos
Espectroscopia de Ressonância de Spin Eletrônica/métodos , Odontologia Legal/métodos , Radioisótopos/análise , Radiometria/métodos , Dente/química , Espectroscopia de Ressonância de Spin Eletrônica/tendências , Odontologia Legal/tendências , Humanos , Radiometria/tendências , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
Appl Radiat Isot ; 62(2): 163-71, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15607443

RESUMO

The objective of the 3rd International Intercomparison on Electron Paramagnetic Resonance (EPR) Tooth Dosimetry was the evaluation of laboratories performing tooth enamel dosimetry below 300 mGy. Participants had to reconstruct the absorbed dose in tooth enamel from 11 molars, which were cut into two halves. One half of each tooth was irradiated in a 60Co beam to doses in the ranges of 30-100 mGy (5 samples), 100-300 mGy (5 samples), and 300-900 mGy (1 sample). Fourteen international laboratories participated in this intercomparison programme. A first analysis of the results and an overview of the essential features of methods applied in different laboratories are presented. The relative standard deviation of results of all methods was better than 27% for applied doses in the range of 79-704 mGy. In the analysis of the unirradiated tooth halves 8% of the samples were identified as outliers with additional absorbed dose above background dose.


Assuntos
Espectroscopia de Ressonância de Spin Eletrônica/métodos , Espectroscopia de Ressonância de Spin Eletrônica/normas , Radiometria/métodos , Radiometria/normas , Padrões de Referência , Dente/química , Dente/efeitos da radiação , Benchmarking/métodos , Carga Corporal (Radioterapia) , Humanos , Técnicas In Vitro , Internacionalidade , Garantia da Qualidade dos Cuidados de Saúde/métodos , Garantia da Qualidade dos Cuidados de Saúde/normas , Doses de Radiação , Eficiência Biológica Relativa , Reprodutibilidade dos Testes , Estudos Retrospectivos , Medição de Risco/métodos , Medição de Risco/normas , Sensibilidade e Especificidade
18.
Appl Radiat Isot ; 62(2): 181-5, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15607445

RESUMO

Three numerical methods were employed to examine how gamma ray doses ranging from 100 mGy to 1Gy could be reconstructed using five human molar teeth. For samples above 28 0mGy, the obtained doses are consistent with each other within the errors but slightly larger than actually given doses. Background doses range from 20 to 170 mGy depending on the methods and samples. Further precise studies would be needed to characterize each method, but it would be recommended to apply several methods to check the reliability of the obtained doses.


Assuntos
Algoritmos , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Dente Molar/química , Dente Molar/efeitos da radiação , Análise Numérica Assistida por Computador , Radiometria/métodos , Carga Corporal (Radioterapia) , Simulação por Computador , Técnicas In Vitro , Modelos Biológicos , Doses de Radiação , Eficiência Biológica Relativa , Reprodutibilidade dos Testes , Medição de Risco/métodos , Medição de Risco/normas , Sensibilidade e Especificidade
19.
Rapid Commun Mass Spectrom ; 17(22): 2550-6, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14608627

RESUMO

The N2O and N2 fluxes emitted from a temperate UK grassland soil after fertiliser application (equivalent to 25 and 75 kg N ha(-1)) were simultaneously measured, using a new automated soil incubation system, which replaces soil atmosphere (N2 dominated) with a He+O2 mixture. Dual isotope and isotopomer ratios of the emitted N2O were also determined. Total N2O and N2 fluxes were significantly lower (P<0.001) in the control (0 kg N) than in the 25 and 75 kg N treatments. The total N2O flux was significantly higher (P<0.001) in the 75 kg N than in the 25 kg N treatment. The general patterns of N2O and N2 fluxes were similar for both fertiliser treatments. The total gaseous N loss in the control treatment was nearly all N2, whereas in the fertiliser treatment more N2O than N2 was emitted from the soil. The ratio N2O/N2 fluxes as measured during the experiment suggested three phases in N2O production, in phase 1 nitrification>denitrification, in phase 2 denitrification>nitrification, and in phase 3 denitrification (and total denitrification)>>nitrification. Dual delta15N and delta18O isotope and isotopomer (delta15Nalpha and delta15Nbeta) value ratios of emitted N2O also pointed towards an increasing dominance of the production of N2O by denitrification and total denitrification. The site preference value from the soil-emitted N2O was lower than the troposphere value. This confirmed that the enhanced troposphere N2O site preference could result from back injection of N2O from the stratosphere. The measurements of N2O/N2 flux ratio and the isotopic content of emitted N2O pointed, independently, to similar temporal trends in N2O production processes after fertiliser application to grassland soil. This confirmed that both measurements are suitable diagnostic tools to study the N2O production process in soils.


Assuntos
Agricultura , Poluentes Ocupacionais do Ar/análise , Fertilizantes , Óxido Nitroso/análise , Solo/análise , Nitrogênio/análise , Poaceae
20.
J Neurol Neurosurg Psychiatry ; 74(7): 908-12, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12810777

RESUMO

OBJECTIVE: To determine the incidence and clinical characteristics of spontaneous haemorrhage into metastatic brain tumours after radiosurgery. METHODS: Intratumour haemorrhage rate, clinical features, and treatment were evaluated in 54 patients with 131 brain metastases of varying origin who were treated using linear accelerator radiosurgery. The marginal dose was maintained constant at 20 or 25 Gy, irrespective of tumour size. RESULTS: Haemorrhage was identified in 7.4% of the metastases (five tumours in four patients) before radiosurgery and in 18.5% (10 tumours in 10 patients) after radiosurgery. In three cases, haemorrhage into the tumour after radiosurgery was symptomatic. Half the haemorrhages occurred within one month of radiosurgery. The changes in tumour size observed at the time of haemorrhage were an increase in one tumour, no change in five, and a decrease in four. Haemorrhage into a tumour after radiosurgery was more likely to occur in female patients, in tumours with a larger volume on pretreatment neuroimaging, and in tumours treated with a larger number of isocentres or a higher maximum dose. Haemorrhagic features in the patients or their tumours on presurgical assessment were not disposing factors to haemorrhage after radiosurgery. CONCLUSIONS: When larger brain metastases are aggressively treated by radiosurgery, better local control may be attained but there may also be a higher risk of haemorrhage soon after the treatment.


Assuntos
Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/cirurgia , Hemorragia Cerebral/etiologia , Complicações Pós-Operatórias/epidemiologia , Radiocirurgia/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Hemorragia Cerebral/epidemiologia , Feminino , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Fatores de Risco
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