Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
1.
Angew Chem Int Ed Engl ; 60(33): 17871-17874, 2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-33978998

RESUMO

The formation and the chemical characterization of single atoms of dubnium (Db, element 105), in the form of its volatile oxychloride, was investigated using the on-line gas phase chromatography technique, in the temperature range 350-600 °C. Under the exactly same chemical conditions, comparative studies with the lighter homologues of Group 5 in the Periodic Table clearly indicate the volatility sequence being NbOCl3 > TaOCl3 ≥ DbOCl3 . From the obtained experimental results, thermochemical data for DbOCl3 were derived. The present study delivers reliable experimental information for theoretical calculations on chemical properties of transactinides.

2.
Nurse Educ Today ; 94: 104552, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32805471

RESUMO

BACKGROUND: The Japanese have had three experiences of radiation disasters: the atomic bombs dropped on Hiroshima and Nagasaki in 1945, and the 2011 Fukushima Nuclear Power Plant disaster. The former two experiences have been covered in compulsory education programs. In light of these incidents, a strong fear of radiation has pervaded people of several generations. In such a situation, the role of nurses is important. When nurses treat residents, their attitudes change depending on how they understand and feel about radiation. The foundations of these attitudes are formed through student education. Hence, it is necessary to explore nursing students' understanding and risk perception of radiation, and the nature of radiation education received. OBJECTIVES: To assess the levels of understanding and risk perception of nursing students regarding radiation. DESIGN: Cross-sectional survey. METHODS: A questionnaire survey was administered to all students (74 first-year, 79 second-year, 65 third-year, and 69 fourth-year students) in the nursing department of a Japanese national university. The response rate was 84%. Respondents were asked to rate their level of understanding of 50 phrases chosen from two supplementary texts about radiation for elementary school students and for middle and high school students, prepared by the Japanese Ministry. Further, they were asked to rate their risk perception for 30 events, and to answer six questions about radiation. RESULTS: It was found that knowledge about radiation among Japanese nursing students was poor, because sufficient radiation education had not been provided. Hence, they displayed a greater fear of X-rays as compared to American students and members of the League of Woman Voters. However, it was also found that an increase in understanding might decrease risk perception. CONCLUSIONS: It was concluded that nursing students require adequate education about radiation, in order to reduce their fear of X-rays and to mitigate their risk perception.


Assuntos
Desastres , Acidente Nuclear de Fukushima , Estudantes de Enfermagem , Estudos Transversais , Feminino , Humanos , Japão , Centrais Nucleares , Percepção , Inquéritos e Questionários
3.
J Am Chem Soc ; 140(44): 14609-14613, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-30358998

RESUMO

We report the first ionization potentials (IP1) of the heavy actinides, fermium (Fm, atomic number Z = 100), mendelevium (Md, Z = 101), nobelium (No, Z = 102), and lawrencium (Lr, Z = 103), determined using a method based on a surface ionization process coupled to an online mass separation technique in an atom-at-a-time regime. The measured IP1 values agree well with those predicted by state-of-the-art relativistic calculations performed alongside the present measurements. Similar to the well-established behavior for the lanthanides, the IP1 values of the heavy actinides up to No increase with filling up the 5f orbital, while that of Lr is the lowest among the actinides. These results clearly demonstrate that the 5f orbital is fully filled at No with the [Rn]5f147s2 configuration and that Lr has a weakly bound electron outside the No core. In analogy to the lanthanide series, the present results unequivocally verify that the actinide series ends with Lr.

4.
J Med Invest ; 63(1-2): 19-26, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27040048

RESUMO

On April 9 2015, the Letter article titled "Measurement of the first ionization potential of lawrencium, element 103" is now published at News and Views on Nature (2015) which has been performed by our remarkably Japanese colleagues of nuclear and radiochemistry at JAEA (Japan Atomic Energy Agency). In this review, the author will state that the isotope separator on-line (ISOL) our regularly used, one of mass separation techniques, with a thermal surface ionization makes possible for determining the ionization potential of lawrencium based on the fruitful fundations of developing the ISOL system until now and also ever studying searches for unknown nuclei and these nuclear decay properties around actinide region in the past 20 years.


Assuntos
Laurêncio/isolamento & purificação , Medicina Nuclear/instrumentação , Radioquímica/instrumentação , Elementos da Série Actinoide/isolamento & purificação , Isótopos/isolamento & purificação , Japão , Espectrometria de Massas/instrumentação , Medicina Nuclear/tendências , Radioquímica/tendências
5.
J Environ Radioact ; 155-156: 7-14, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26875111

RESUMO

Following the Fukushima Nuclear Power Plant accident, the Japanese government created two supplemental texts about radiation reflecting the accident for elementary, middle school, and high school students. These texts were made to explain radiation and consequently to obtain public consent for the continuation of the nuclear program. The present study aimed to evaluate the appropriateness of the content of the texts and to collect the basic data on the level of understanding necessary to improve radiation education. Lectures on radiology including nuclear energy and the Fukushima accident were given to 44 fourth-year dental students in 2013. The questionnaire was administered in 2014 when these students were in their sixth-year. The survey was also administered to 40 first-year students and 41 fourth-year students who hadn't any radiology lectures. Students rated their level of understanding of 50 phrases used in the texts on a four-point scale (understanding = 3, a little knowledge = 2, having heard = 1, no knowledge = 0). Questions on taking an advanced physics course in high school and means of learning about radiation in daily life were also asked. The level of understanding of phrases in the supplemental text for middle and high school students was significantly higher among sixth-year students (mean = 1.43) than among first-year (mean = 1.12) or fourth-year (mean = 0.93) students (p < 0.05). Overall, the level of understanding was low, with scores indicating that most students knew only a little. First-year students learning about radiation from television but four-year and six-year students learning about radiation from newspaper scored significantly higher (p < 0.05). It was concluded that radiation education should be improved by using visual material and preparing educators to teach the material for improving the public's understanding of radiation use-especially nuclear power generation because the phrases used in the supplementary texts are very difficult for students to understand.


Assuntos
Compreensão , Acidente Nuclear de Fukushima , Publicações Governamentais como Assunto , Educação em Saúde/métodos , Radiologia/educação , Governo Federal , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Japão , Centrais Nucleares , Estudantes de Odontologia , Inquéritos e Questionários
6.
Dent Mater J ; 34(6): 814-21, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26632229

RESUMO

Although the accumulation and distribution of metals from metallic orthodontic appliances in the oral mucosa have been studied extensively, they remain unclear because their concentration is quite low. In this study, metal specimens (Ni, Ni-Ti, and Co-Cr) were sutured in the unilateral oral mucosa of rats, and the distribution of the eluted elements in the mucosal tissue was estimated using inductively coupled plasma mass spectrometry (ICP-MS) and synchrotron radiation X-ray fluorescence analysis (SR-XRF). While the infiltrations of Ni, Co, and Cr into the oral mucosal connective tissue were observed with SR-XRF, significant increases were only found in Ni from the pure Ni group and Cr from the Co-Cr group. Furthermore, Ni and Co were estimated as hydrated ions while Cr was estimated in oxide form through X-ray absorption fine structure (XAFS) analysis.


Assuntos
Mucosa Bucal/metabolismo , Animais , Ligas de Cromo/química , Feminino , Microscopia de Fluorescência , Níquel/química , Aparelhos Ortodônticos , Ratos , Ratos Wistar , Espectrometria por Raios X , Espectrofotometria Atômica , Titânio/química , Oligoelementos/química , Espectroscopia por Absorção de Raios X
7.
Nihon Hoshasen Gijutsu Gakkai Zasshi ; 71(10): 983-93, 2015 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-26490232

RESUMO

The low-level radioactivity of a (68)Ge/(68)Ga generator is a suitable tool for measuring radioactive growth and decay after (68)Ga milking due to their desirable nuclear decay properties, such as the EC decay of (68)Ge with no γ-ray emission andthe ß(+) decay of (68)Ga with a weak γ-ray emission. To experience andund erstandrad ioactive equilibrium during a university laboratory course, we surveyedandtestedthe production of a small amount of (68)Ge and set up educational programs to manufacture a (68)Ge/(68)Ga generator for measuring the growth andd ecay of (68)Ga. The irradiation of natGa with 25 µA of a 30 MeV proton beam from a cyclotron for 4 h yields ca. 111 MBq of (68)Ge, which was sufficient to supply to several universities. For use as the adsorbent of the generator column, particles of hydrated tin (VI) oxide were prepared from precipitated tin hydroxide gel. Repeated elution of (68)Ga from the handmade (68)Ge/(68)Ga generator gave constant amounts of (68)Ga with acceptable breakthrough of (68)Ge. The feedback from the student's experience with the (68)Ge/(68)Ga generator was evaluatedby annual questionnaire surveys, which were given to all students taking the course every year from 2012 to 2014. It has been made clear that more than half of the students were interested in the (68)Ge/(68)Ga generator program, andthis interest increasedfrom 54.9%in 2012 to 78.6%in 2014. A low-level radioactive (68)Ge/(68)Ga generator is thus expectedto be a suitable experimental tool for demonstrating the phenomenon of radioactivity to students in an intriguing way.


Assuntos
Radioisótopos de Gálio , Germânio , Radioquímica/educação , Radioisótopos , Geradores de Radionuclídeos , Ciclotrons , Germânio/isolamento & purificação
8.
J Nutr Sci Vitaminol (Tokyo) ; 61(1): 20-7, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25994136

RESUMO

Although iron is an essential trace metal, its presence in excess causes oxidative stress in the human body. Recent studies have indicated that iron storage is a risk factor for type 2 diabetes mellitus. Dietary iron restriction or iron chelation ameliorates symptoms of type 2 diabetes in mouse models. However, whether iron content in the body changes with the development of diabetes is unknown. Here, we investigated the dynamics of iron accumulation and changes in iron absorption-related genes in mice that developed obesity and diabetes by consuming a high-fat diet (HFD-fed mice). HFD-fed mice (18-20 wk) were compared with control mice for hematologic features, serum ferritin levels, and iron contents in the gastrocnemius muscle, heart, epididymal fat, testis, liver, duodenum, and spleen. In addition, the spleen was examined histologically. Iron absorption-related gene expression in the liver and duodenum was also examined. Hemoglobin and serum ferritin levels were increased in HFD-fed mice. The HFD-fed mice showed iron accumulation in the spleen, but not in the heart or liver. Increased percentages of the splenic red pulp and macrophages were observed in HFD-fed mice and iron accumulation in the spleen was found mainly in the splenic red pulp. The HFD-fed mice also showed decreased iron content in the duodenum. The mRNA expression of divalent metal transporter-1 (DMT-1), an iron absorption-related gene, was elevated in the duodenum of HFD-fed mice. These results indicate that iron accumulation (specifically accumulation in the spleen) is enhanced by the development of type 2 diabetes induced by HFD.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Dieta Hiperlipídica/efeitos adversos , Gorduras na Dieta/administração & dosagem , Ferro da Dieta/metabolismo , Ferro/metabolismo , Baço/metabolismo , Animais , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Diabetes Mellitus Tipo 2/etiologia , Gorduras na Dieta/efeitos adversos , Duodeno/metabolismo , Ferritinas/sangue , Hemoglobinas/metabolismo , Absorção Intestinal/genética , Masculino , Camundongos Endogâmicos C57BL , Obesidade/etiologia , Obesidade/metabolismo , Estresse Oxidativo , RNA Mensageiro/metabolismo
9.
Artigo em Inglês | MEDLINE | ID: mdl-24109823

RESUMO

We have developed bone cement introducing Strontium (Sr) to promote early bone regeneration. To prolong the release duration of Sr, we applied inorganic Sr filler for containing into the cement powder. The purpose of this study is to evaluate the mechanical properties, crystallinic properties, and ion release activities, especially Sr anion, of this cement. Alpha-TCP powder was mixed with Sr filler, with 0.1wt%, 0.5wt%, 1.0wt%, and 5.0wt%. These were mixed with mixing liquid and formed for each test. They were incubated and crystalized in 95% moisture for 1 week. The mechanical properties were studied by the compression, the diametral tensile strength and 4-point vending. Tested specimens were evaluated by X-ray diffraction(XRD) and scanning electron microscopic(SEM) imaging. The ion release behaviors were measured by inductively coupled plasma mass spectrometry(ICP-MS). The mechanical properties were increased in consistency of filler, but decreased in some samples because of declining the apatite matrix. And the Sr release showed interesting results as the sequential resource of Sr. By adjusting the mixing ratio or considering the application of these Sr releasable cements, this material would show good performance by its strength and longer Sr release for bone regeneration.


Assuntos
Apatitas/farmacologia , Cimentos Ósseos/farmacologia , Substitutos Ósseos/farmacologia , Teste de Materiais , Estrôncio/farmacologia , Força Compressiva/efeitos dos fármacos , Cristalização , Injeções , Microscopia Eletrônica de Varredura , Resistência à Tração/efeitos dos fármacos , Difração de Raios X
10.
Magn Reson Med Sci ; 12(3): 235-40, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23857146

RESUMO

PURPOSE: Our purposes were to establish suitable conditions for proton magnetic resonance spectroscopy (MRS) to measure dynamic changes in alcohol concentration in the human brain, to evaluate these changes, and to compare the findings with data from analysis of breath vapor and blood samples. MATERIALS AND METHODS: We evaluated 4 healthy volunteers (mean age 26.5 years; 3 males, one female) with no neurological findings. All studies were performed with 3-tesla clinical equipment using an 8-channel head coil. We applied our modified single-voxel point-resolved spectroscopy (PRESS) sequence. Continuous measurements of MRS, breath vapor, and blood samples were conducted before and after the subjects drank alcohol with a light meal. The obtained spectra were quantified by LCModel Ver. 6.1, and the accuracy of the MRS measurements was estimated using the estimated standard deviation expressed in percentage (%SD) as a criterion. RESULTS: Alcohol peaks after drinking were clearly detected at 1.2 ppm for all durations of measurement. Good correlations between breath vapor or blood sample and MRS were found by sub-minute MRS measurement. The continuous measurement showed time-dependent changes in alcohol in the brain and various patterns that differed among subjects. CONCLUSIONS: The clinical 3T equipment enables direct evaluation of sub-minute changes in alcohol metabolism in the human brain.


Assuntos
Algoritmos , Encéfalo/metabolismo , Etanol/metabolismo , Interpretação de Imagem Assistida por Computador/instrumentação , Imageamento por Ressonância Magnética/instrumentação , Espectroscopia de Ressonância Magnética/instrumentação , Adulto , Testes Respiratórios , Desenho de Equipamento , Análise de Falha de Equipamento , Etanol/sangue , Feminino , Humanos , Masculino , Taxa de Depuração Metabólica , Especificidade de Órgãos , Projetos Piloto , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Distribuição Tecidual , Adulto Jovem
11.
J Am Chem Soc ; 126(16): 5219-24, 2004 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-15099106

RESUMO

Fluoride complexation of element 104, rutherfordium (Rf), produced in the 248Cm(18O,5n)261Rf reaction has been studied by anion-exchange chromatography on an atom-at-a-time scale. The anion-exchange chromatographic behavior of Rf was investigated in 1.9-13.9 M hydrofluoric acid together with those of the group-4 elements Zr and Hf produced in the 18O-induced reactions on Ge and Gd targets, respectively. It was found that the adsorption behavior of Rf on anion-exchange resin is quite different from those of Zr and Hf, suggesting the influence of relativistic effects on the fluoride complexation of Rf.

12.
J Comput Assist Tomogr ; 27(3): 449-53, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12794615

RESUMO

OBJECTIVE: The purpose of this study was to evaluate the reproducibility of in vivo quantitative proton MR spectroscopy (MRS) by repeated-measure analysis of variance and intraclass correlation coefficient (ICC) including assessment of both inter- and intrasubject variation. METHODS: The concentration of metabolites was quantified using long-TR and short-TE stimulated-echo acquisition mode sequences with a quadrature head coil. All preparation procedures for MRS measurement except volume of interest determination were done by an automatic preparation scanning system equivalent to a clinical setting. Analyses were conducted by an LCModel running based on our original basis set by two different reference methods. RESULTS: The ICC showed a good correlation (r = 0.61-0.99) in any metabolite and almost the same value between the two different reference methods, but the concentration of myoinositol had a large intersubject variation. CONCLUSION: Our results suggest that the reproducibility of quantified metabolite concentration is acceptable in the clinical setting regardless of the reference method, although quantified values may have different intersubject variations.


Assuntos
Espectroscopia de Ressonância Magnética , Adulto , Química Encefálica , Feminino , Humanos , Masculino , Prótons , Reprodutibilidade dos Testes
13.
J Magn Reson Imaging ; 17(6): 722-5, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12766902

RESUMO

This is a report on a case of carbohydrate-deficient glycoprotein syndrome (CDGS) with neurological deficits. Magnetic resonance (MR) images showed remarkable atrophy of the cerebellum and brainstem, and hypointensity was seen in the pallidum on diffusion-weighted images (DWI), suggesting deposits of metal substances. In the cerebellum, proton MR spectroscopy (MRS) showed decreased concentrations of N-acetylaspartate and a complex of glutamine and glutamate (Glx) while the concentration of myo-inositol was increased, indicating neuronal impairment and gliosis. In the parietal lobe, there was an increased concentration of Glx, possibly reflecting dysfunction caused by liver injury.


Assuntos
Encéfalo/patologia , Defeitos Congênitos da Glicosilação/diagnóstico , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Adolescente , Humanos , Masculino
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA