Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Rev Sci Instrum ; 91(2): 023303, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32113443

RESUMO

An innovative 18 GHz HIISI (Heavy Ion Ion Source Injector) room temperature Electron Cyclotron Resonance (ECR) ion source (ECRIS) has been designed and constructed at the Department of Physics, University of Jyväskylä (JYFL), for the nuclear physics program of the JYFL Accelerator Laboratory. The primary objective of HIISI is to increase the intensities of medium charge states (M/Q ≅ 5) by a factor of 10 in comparison with the JYFL 14 GHz ECRIS and to increase the maximum usable xenon charge state from 35+ to 44+ to serve the space electronics irradiation testing program. HIISI is equipped with a refrigerated permanent magnet hexapole and a noncylindrical plasma chamber to achieve very strong radial magnetic confinement with Brad = 1.42 T. The commissioning of HIISI began in Fall 2017, and in Spring 2019, it has met the main objectives. As an example, the intensity of the Xe27+ ion beam has improved from 20 µA to 230 µA. In addition, the beam intensity of the Xe44+ ion beam has exceeded the requirement set by the irradiation testing program. The performance of HIISI is comparable to superconducting ECR ion sources with the same maximum microwave frequency of 18 GHz and a total power of 3 kW. For example, Ar16+ and Xe30+ ion beam intensities of 130 µA and 106 µA, respectively, have been obtained with a total microwave power of 3 kW distributed between 18, 17.4, and 14.5 GHz frequencies. The ion beams have been extracted through an 8 mm plasma electrode aperture using 15-17 kV extraction voltage. The latest development work, extracted ion beam intensities, special features, and future prospects of HIISI are presented in this paper.

2.
Rev Sci Instrum ; 91(1): 013304, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32012571

RESUMO

Cumulative ion confinement times are probed by measuring decaying ion current transients in pulsed material injection mode. The method is applied in a charge breeder and conventional ECRIS yielding mutually corroborative results. The cumulative confinement time estimates vary from approximately 2 ms-60 ms with a clear dependence on the ion charge-to-mass ratio-higher charges having longer residence times. The long cumulative confinement times are proposed as a partial explanation to recently observed unexpectedly high ion temperatures. The results are relevant for rare ion beam (RIB) production as the confinement time and the lifetime of stable isotopes can be used for estimating the extracted RIB production efficiency.

3.
Rev Sci Instrum ; 91(1): 013318, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32012583

RESUMO

Electron Cyclotron Resonance Ion Source (ECRIS) plasmas contain high-energy electrons and highly charged ions implying that only noninvasive methods such as optical emission spectroscopy are reliable in their characterization. A high-resolution spectrometer (10 pm FWHM at 632 nm) enabling the detection of weak emission lines has been developed at University of Jyväskylä, Department of Physics (JYFL) for this purpose. Diagnostics results probing the densities of ions, neutral atoms, and the temperature of the cold electron population in the JYFL 14 GHz ECRIS are described. For example, it has been observed that the cold electron temperature drops from 40 eV to 20 eV when the extraction voltage of the ion source is switched off, accompanied by two orders of magnitude decrease in Ar9+ optical emission intensity, suggesting that diagnostics results of ECRIS plasmas obtained without the extraction voltage are not depicting the plasma conditions of normal ECRIS operation. The relative changes of the plasma optical emission and the ion beam current have been measured in CW and amplitude modulation operation mode of microwave injection. It is concluded that in the CW mode, the ion currents could be limited by diffusion transport and electrostatic confinement of the ions rather than beam formation in the extraction region and subsequent transport. The high resolution of the spectrometer allows determining the ion temperature by measuring the Doppler broadening of the emission lines and subtracting the wavelength dependent instrumental broadening. The measured ion temperatures in the JYFL 14 GHz ECRIS are between 5 and 28 eV, depending on the plasma species and charge state. Gas mixing is shown to be an effective method to decrease the ion temperature of high charge state argon ions from 20 eV in pure argon discharge to 5 eV when mixed with oxygen.

4.
Rev Sci Instrum ; 90(11): 113321, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31779446

RESUMO

The order-of-magnitude performance leaps of ECR ion sources over the past decades result from improvements to the magnetic plasma confinement, increases in the microwave heating frequency, and techniques to stabilize the plasma at high densities. Parallel to the technical development of the ion sources themselves, significant effort has been directed into the development of their plasma diagnostic tools. We review the recent results of Electron Cyclotron Resonance Ion Source (ECRIS) plasma diagnostics highlighting a number of selected examples of plasma density, electron energy distribution, and ion confinement time measurements, obtained mostly with the second-generation sources operating at frequencies from 10 to 18 GHz. The development of minimum-B ECR ion sources based on the superposition of solenoid and sextupole fields has long relied on semiempirical scaling laws for the strength of the magnetic field with increasing plasma heating frequency. This approach is becoming increasingly difficult with the looming limits of superconducting technologies being able to satisfy the magnetic field requirements at frequencies approaching 60 GHz. Thus, we discuss alternative ECRIS concepts and proposed modifications to existing sources that are supported by the current understanding derived from the plasma diagnostics experiments.

5.
Eur J Pain ; 22(5): 1016-1025, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29388281

RESUMO

OBJECTIVE: The Pain Coping Questionnaire (PCQ), the first validated pain coping measurement developed specifically for children, has lacked proper validation in Finnish. The original PCQ by Reid et al. (Pain 1998; 76; 83-96) comprises eight-first-order and three higher-order scales. The aim herein was to determine the factor structure and validity of the Finnish PCQ translation in Finnish children. METHODS: Exploratory factor analysis was used for the first-order and higher-order classification of 91 recruited patients aged 8-15. Cronbach's alpha was used for reliability. Relationships between the Children's Depression Inventory, patient-reported pain frequency and pain coping strategies were examined. RESULTS: Analyses were executed with 38 items; one was excluded. A structure of eight-first-order (Internalizing/Catastrophizing [IC], Positive Self-Statements [PSS], Information Seeking [IS], Seeking Social Support [SSS], Cognitive Distraction [CD], Externalizing [EXT], Behavioural Distraction [BD], Problem Solving [PS]) and three higher-order scales (Approach [APP], Emotion-Focused Avoidance [EFA], Distraction [DIS]) proved the most consistent. Four first-order scales (PSS, CD, EXT, BD) emerged as identical to the original solution. Internal consistency reliability coefficients for all individual first- and second-order scales were satisfactory. A higher CDI score was positively related to EFA and negatively to DIS, and pain frequency positively related to APP and EFA. CONCLUSION: The exploratory factor analysis of the PCQ provided a both culturally and statistically satisfactory structure in the Finnish translation. This supports the reliability and validity of the PCQ in future national use and the value of the questionnaire also outside English-speaking countries. SIGNIFICANCE: This study showed both culturally and statistically satisfactory factor structure of PCQ in the Finnish translation. This result supports reliability and validity of the PCQ in the national use in the future. The result shows that the PCQ is a reliable method to be used in different linguistic and cultural surroundings and, thus, encourages using it in various countries. The data consist of two patient groups, adolescents with JIA and musculoskeletal pain. Pain and specifically coping with pain are important aspects of clinical work. A valid pain coping scale may enhance distinguishing vulnerable pain coping style in children and adolescent before pain becomes chronic.


Assuntos
Adaptação Psicológica/fisiologia , Emoções/fisiologia , Dor/psicologia , Apoio Social , Adolescente , Catastrofização/psicologia , Criança , Feminino , Finlândia , Humanos , Masculino , Medição da Dor/métodos , Reprodutibilidade dos Testes , Inquéritos e Questionários , Traduções
6.
Acta Anaesthesiol Scand ; 60(6): 790-9, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26866628

RESUMO

BACKGROUND: Chloride-rich fluids have been found to associate with an increased risk for acute kidney injury (AKI) among intensive care unit (ICU) patients. Studies evaluating the association of plasma chloride (Cl) with the development of AKI are few. We hypothesized that higher plasma Cl is associated with an increased risk for the development of AKI. METHODS: In this sub-study of the prospective FINNAKI study, we analyzed Cl values measured during ICU stay in two ICUs at a tertiary center including 445 patients. We calculated time-weighted mean values within the first 24 h in ICU for plasma Cl (ClTWM 24 ). We analyzed the association of ClTWM 24 primarily with the development of AKI, and secondarily with 90-day mortality. RESULTS: Based on the first measured Cl value, 350 of 445 patients [78.7 (95 CI, 74.8-82.5)] had hyperchloremia (P-Cl > 106 mmol/l) and 48 [10.8 (95 CI, 7.9-13.7)] severe hyperchloremia (P-Cl > 114 mmol/l). Altogether 217 of 445 [48.8% (95% CI 44.2-53.4%)] patients developed AKI. Of these 217, AKI was diagnosed in 62 (28.6%) after 24 h from ICU admission and were included in the analysis regarding development of AKI. ClTWM 24 was associated with an increased risk for the development of AKI (OR1.099; 1.003-1.205) after multivariable adjustments. According to ClTWM 24 , no difference in 90-day mortality between severely hyperchloremic patients and others existed. CONCLUSIONS: More than three of four critically ill patients had hyperchloremia and 1 of 10 had its severe form. Higher time-weighted mean chloride was independently associated with an increased risk for AKI.


Assuntos
Injúria Renal Aguda/sangue , Estado Terminal , Cuidados Críticos , Humanos , Unidades de Terapia Intensiva , Estudos Prospectivos
7.
Eur J Clin Nutr ; 68(5): 587-91, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24518750

RESUMO

UNLABELLED: BACKGROUND/ OBJECTIVES: We evaluated plant sterol and stanol (PS) intakes from natural sources and enriched foods in the Finnish population-based national FINDIET 2007 Survey. In addition, we compared the users and nonusers of PS-enriched foods in terms of their characteristics and dietary intake. SUBJECTS/METHODS: This was a cross-sectional population-based study on 958 men and 1080 women aged 25-74. Users and nonusers of PS-enriched products were compared with respect to sex, age, education, region, cholesterol-lowering medication and cholesterol-lowering diet. Intakes of PS, energy, energy nutrients, fat composition, cholesterol and dietary fibre were calculated on the basis of a 48-h dietary recall. The distribution of PS intake was assessed for the users of enriched products. RESULTS: PS-enriched foods were used by 9.5% of all subjects. The usage increased significantly with age (P<0.001) and level of education (P=0.01). The usage of enriched products was more common among those following a cholesterol-lowering medication or diet (P<0.001 for both). Among users, the mean intake of PS was 2.2 g/d for men and 1.6 g/d for women, and among nonusers it was 363 mg/d for men and 286 mg/d for women. The majority of users received less than 2 g/d of PS from enrichment, but 20% of users obtained more than 3 g of PS per day. CONCLUSIONS: The intake of PS can reach several grams in a subgroup of subjects consuming PS-enriched foods. The manufacturers' recommendations on PS-enriched food consumption are not consistently followed, and customer guidance needs to be improved.


Assuntos
Comportamento Alimentar , Alimentos Fortificados , Fitosteróis/administração & dosagem , Sitosteroides/administração & dosagem , Adulto , Idoso , Anticolesterolemiantes/administração & dosagem , LDL-Colesterol/sangue , Estudos Transversais , Registros de Dieta , Dieta com Restrição de Gorduras , Feminino , Finlândia , Humanos , Masculino , Rememoração Mental , Pessoa de Meia-Idade , Inquéritos Nutricionais
8.
Int J Sports Med ; 30(5): 348-53, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19301214

RESUMO

The aim of the study was to determine changes in body composition and physical fitness during military service. A prospective cohort study of 140 healthy male conscripts was conducted. We examined subject characteristics, aerobic performance and muscle strength, and assessed body composition using dual-energy X-ray absorptiometry (DEXA) three times. Conscripts' mean baseline weight (79.5 kg) decreased by 2 kg during the first 3 months, but increased by 0.9 kg during the second 3-month period (p<0.001). Fat mass measured by DEXA decreased by 3.2 kg during the first but increased by 0.8 kg during the second 3-month period (p<0.001). Throughout the 6-month study, an increase was seen in distance of 12-min run test (from 2 380 m to 2 530 m; p<0.001), and muscle strength score (from 6.5 to 9.5 p<0.001). Finnish military training seems to have beneficial effects on physical fitness. However, considering the relatively modest changes in body fat and physical fitness seen in conscripts with average BMIs at baseline, design of diverse training programmes for the varying baseline BMI levels are warranted to improve the physical fitness results.


Assuntos
Desempenho Atlético/fisiologia , Composição Corporal/fisiologia , Força Muscular/fisiologia , Absorciometria de Fóton , Adolescente , Índice de Massa Corporal , Estudos de Coortes , Finlândia , Humanos , Masculino , Militares/estatística & dados numéricos , Aptidão Física/fisiologia , Estudos Prospectivos , Adulto Jovem
9.
Int J Sports Med ; 29(11): 872-7, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18516767

RESUMO

To investigate the effects of a rapid weight reduction program under authentic pre-competition conditions, eighteen elite wrestlers were studied with dual-energy X-ray absorptiometry (DXA) before and after two to three weeks' weight reduction regimens. In order to establish the degree of dehydration and hormonal status, blood samples were collected to obtain blood chemistry, electrolytes and endocrinological parameters after both DXA measurements. The mean weight loss was 8.2 +/- 2.3 % and it was constituted by the mean reductions of fat mass of 16 +/- 6.9 % (p < or = 0.001) and lean body mass of 7.9 +/- 2.5 %. The rapid weight reduction caused significant dehydration which was noticed as increased blood hemoglobin (7.8 +/- 5.9 %, p < or = 0.001), hematocrit (11.3 +/- 6.8 %, p < or = 0.001), and serum creatinine (35 +/- 23 %, p < or = 0.001). There was a significant decrease in serum testosterone (63 +/- 33 %, p < or = 0.001) and luteinizing hormone (54 +/- 47 %, p < or = 0.001) concentrations. A reduced body weight correlated with decreased serum testosterone concentration (r = 0.53, p < or = 0.024). Serum sex hormone binding globulin concentration increased significantly (40 +/- 21 %, p < or = 0.001). The results suggest that even short-term weight reduction may have marked effects on body composition, blood chemistry and hormonal parameters. It may constitute a possible health risk at least in a growing adolescent athlete.


Assuntos
Peso Corporal , Desidratação/sangue , Sudorese , Testosterona/sangue , Redução de Peso , Luta Romana , Absorciometria de Fóton , Adolescente , Adulto , Antropometria , Composição Corporal , Comportamento Competitivo , Humanos , Masculino , Projetos Piloto , Medição de Risco , Globulina de Ligação a Hormônio Sexual , Estatística como Assunto , Fatores de Tempo , Adulto Jovem
10.
Skeletal Radiol ; 22(1): 11-6, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8430340

RESUMO

Lysinuric protein intolerance (LPI) is an autosomal recessive disease caused by defective transport of the cationic amino acids lysine, arginine, and ornithine at the cell membrane. About 80 patients with LPI have been described worldwide, almost half of them in Finland. The symptoms appear in early childhood as a failure to thrive, growth retardation, muscular hypotonia, and episodes of stupor after protein-rich meals. Twenty-nine Finnish patients (current median age 24.8 years, range 3.7-47.9 years) over a mean follow-up time of 18.1 years (range 1.2-27.2 years) had 57 fractures after minor trauma, mostly in childhood. Their 440 skeletal radiographs showed severe osteoporosis (13/29), controversially abnormal thickening of cortex of the metacarpals (7/29), or thin cortices of the long bones (5/29), endplate impression of vertebrae (8/29), rickets-like metaphyses (2/29), or early destruction of cartilage (3/29). Skeletal maturation was delayed by 1-5 years in 23 of 24 patients. There was no correlation between fracture incidence, radiological bone structure, and delayed skeletal maturation.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/diagnóstico por imagem , Arginina/metabolismo , Osso e Ossos/diagnóstico por imagem , Proteínas Alimentares/metabolismo , Lisina/metabolismo , Ornitina/metabolismo , Adolescente , Adulto , Erros Inatos do Metabolismo dos Aminoácidos/complicações , Erros Inatos do Metabolismo dos Aminoácidos/fisiopatologia , Transporte Biológico , Desenvolvimento Ósseo , Criança , Pré-Escolar , Feminino , Seguimentos , Fraturas Ósseas/diagnóstico por imagem , Fraturas Ósseas/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/diagnóstico por imagem , Osteoporose/etiologia , Radiografia
12.
Exp Mol Pathol ; 48(1): 97-102, 1988 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3335254

RESUMO

Accumulation of autophagic vacuoles (AVs) is a phenomenon observed in various cells treated with the microtubule inhibitor vinblastine. In order to test whether the accumulation of AVs is a result of retarded fusion of autophagosomes and lysosomes an investigation was carried out to ascertain whether other antimicrotubular drugs, e.g., nocodazole and griseofulvin, also induce accumulation of AVs. Ehrlich ascites tumor cells were incubated with nocodazole (20 micrograms/ml) or griseofulvin (50 micrograms/ml). Morphometric analyses were performed after incubation periods of 3, 30, 60, and 120 min. The volume densities of autophagic vacuoles did not differ significantly from the control values after the various incubation periods tested. It was concluded that intact microtubules are not needed in the fusion of autophagosomes and lysosomes and that vinblastine accelerates the rate of AV formation.


Assuntos
Benzimidazóis/toxicidade , Carcinoma de Ehrlich/ultraestrutura , Griseofulvina/toxicidade , Organoides/ultraestrutura , Vacúolos/ultraestrutura , Animais , Autofagia , Carcinoma de Ehrlich/patologia , Camundongos , Camundongos Endogâmicos , Microscopia Eletrônica , Nocodazol , Vacúolos/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...