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1.
Nat Commun ; 13(1): 6129, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36253344

RESUMO

Effective models focused on pertinent low-energy degrees of freedom have substantially contributed to our qualitative understanding of quantum materials. An iconic example, the Kondo model, was key to demonstrating that the rich phase diagrams of correlated metals originate from the interplay of localized and itinerant electrons. Modern electronic structure calculations suggest that to achieve quantitative material-specific models, accurate consideration of the crystal field and spin-orbit interactions is imperative. This poses the question of how local high-energy degrees of freedom become incorporated into a collective electronic state. Here, we use resonant inelastic x-ray scattering (RIXS) on CePd3 to clarify the fate of all relevant energy scales. We find that even spin-orbit excited states acquire pronounced momentum-dependence at low temperature-the telltale sign of hybridization with the underlying metallic state. Our results demonstrate how localized electronic degrees of freedom endow correlated metals with new properties, which is critical for a microscopic understanding of superconducting, electronic nematic, and topological states.

2.
Sci Rep ; 12(1): 8079, 2022 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-35577866

RESUMO

Since the commercial exploitation of marine oil and gas reserves began in the middle of the twentieth century, extensive networks of offshore infrastructure have been installed globally. Many of the structures are now nearing the end of their operational lives and will soon require decommissioning, generating renewed interest in their environmental impacts and in the ecological consequences of their removal. However, such work requires selection of a subsample of assets for surveying; censuses of the entire 'population' in any given jurisdiction are practically impossible due to their sheer number. It is important, therefore, that the selected sample is sufficiently representative of the population to draw generalized conclusions. Here, a formal clustering methodology, partitioning around medoids, was used to produce a typology of surface-piercing oil and gas platforms in the North Sea. The variables used for clustering were hydrocarbon product, operational state, platform design and material, and substructure weight. Assessing intra-cluster variability identified 13 clusters as the optimum number. The most important distinguishing variable was platform type, isolating floating platforms first, then concrete gravity-based and then fixed steel. Following clustering, a geographic trend was evident, with oil production more prevalent in the north and gas in the south. The typology allows a representative subset of North Sea oil and gas platforms to be selected when designing a survey, or an assessment of the representativeness of a previously selected subset of platforms. This will facilitate the efficient use of the limited funding available for such studies.


Assuntos
Meio Ambiente , Hidrocarbonetos , Mar do Norte , Campos de Petróleo e Gás
3.
J Hum Hypertens ; 36(1): 61-68, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-33536549

RESUMO

The goal of this study was to examine associations of measures of maternal glucose metabolism and blood pressure during pregnancy with blood pressure at follow-up in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) cohort. The HAPO Follow-Up Study included 4747 women who had a 75-g oral glucose tolerance test (OGTT) at ~28 weeks' gestation. Of these, 4572 women who did not have chronic hypertension during their pregnancy or other excluding factors, had blood pressure evaluation 10-14 years after the birth of their HAPO child. Primary outcomes were systolic blood pressure (SBP), diastolic blood pressure (DBP), and hypertension (SBP ≥ 140 and/or DBP ≥ 90 or treatment for hypertension) at follow-up. Blood pressure during pregnancy was associated with all blood pressure outcomes at follow-up independent of glucose and insulin sensitivity during pregnancy. The sum of glucose z-scores was associated with blood pressure outcomes at follow-up but associations were attenuated in models that included pregnancy blood pressure measures. Associations with SBP were significant in adjusted models, while associations with DBP and hypertension were not. Insulin sensitivity during pregnancy was associated with all blood pressure outcomes at follow-up, and although attenuated after adjustments, remained statistically significant (hypertension OR 0.79, 95%CI 0.68-0.92; SBP beta -0.91, 95% CI -1.34 to -0.49; DBP beta -0.50, 95% CI -0.81 to -0.19). In conclusion, maternal glucose values at the pregnancy OGTT were not independently associated with maternal blood pressure outcomes 10-14 years postpartum; however, insulin sensitivity during pregnancy was associated independently of blood pressure, BMI, and other covariates measured during pregnancy.


Assuntos
Glicemia , Pressão Sanguínea , Hiperglicemia , Glicemia/metabolismo , Feminino , Seguimentos , Glucose , Humanos , Período Pós-Parto , Gravidez , Resultado da Gravidez
4.
Pediatr Diabetes ; 21(7): 1277-1284, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32738012

RESUMO

BACKGROUND: Youth with type 1 diabetes (T1D) are encouraged to participate in physical activity (PA). Studies have identified fear of hypoglycemia (FOH) as a barrier to participating in PA. OBJECTIVES: To examine (a) PA patterns in youth with T1D by age group and (b) the relationship between both parental and youth FOH and youth PA. METHODS: A cross-sectional analysis from the SEARCH cohort study visit of youth ages 10 to 17 years with T1D (n = 1129) was conducted. Linear regression models estimated the association between self-reported number of days of vigorous PA (VPA) and moderate PA (MPA) and both youth- and parent-reported FOH. Multivariable models were adjusted for age, sex, race, duration of T1D, HbA1c, use of continuous glucose monitoring (CGM), recent severe hypoglycemia, primary insulin regimen, and BMI. RESULTS: Participants were 52% female, had mean (sd) age 14.4 (4.2) years, diabetes duration 7.5 years (1.8), HbA1c 9.2% (1.7). Older youth were less likely to engage in VPA (P < .01), or sports teams (P < .01), but more likely to engage in MPA (P < .01). Higher youth FOH (behavior subscale) was associated with increased levels of VPA (ß (se) 0.30 (0.11), P = .01) but not significantly associated with MPA (P = .06). There was no statistically significant association between parental FOH and youth PA. CONCLUSIONS: In SEARCH participants with T1D, VPA, and team sports participation declined with age, while MPA increased. We observed that higher scores on the youth FOH behavioral subscale were associated with increased VPA levels, suggesting that FOH may be less of a barrier to PA than previously thought.


Assuntos
Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/psicologia , Exercício Físico/psicologia , Medo , Hipoglicemia/etiologia , Hipoglicemia/psicologia , Adolescente , Automonitorização da Glicemia , Criança , Estudos de Coortes , Estudos Transversais , Diabetes Mellitus Tipo 1/terapia , Feminino , Humanos , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Masculino , Pais/psicologia
5.
Diabet Med ; 36(8): 1028-1036, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31050009

RESUMO

AIM: To examine the distribution and association of sociodemographic, adherence, and barriers-to-care factors in relation to glycaemic control within insulin regimens in US children with Type 1 diabetes in the SEARCH for Diabetes in Youth Study. METHODS: Self- or parent-reported data from 1095 children with Type 1 diabetes aged 10-17 years were collected on insulin regimen, sociodemographics, diabetes self-management, diabetes-related family conflict and barriers to care. Multivariable logistic regression analysis identified poor glycaemic control correlates within each insulin regimen. RESULTS: Participants included 694 children on insulin pump therapy, 188 receiving basal-bolus injections, and 213 on a mixed insulin regimen. Of these, 28.5%, 45.2% and 51.2%, respectively, had poor glycaemic control [HbA1c ≥ 80 mmol/mol (9.5%)]. Family conflict between parent and child regarding diabetes management was the only factor significantly associated with poor glycaemic control in all insulin regimens (insulin pump, P≤ 0.0001; basal-bolus injections, P=0.0002; mixed insulin regimen, P=0.0103). For children on insulin pump, poor control was significantly associated with non-white race (P=0.0008), living in multiple households (P=0.0331), having Medicaid insurance (P=0.0090), and decreased insulin adherence (P<0.0001). For children on a mixed insulin regimen, living in multiple households (P=0.0256) and not spending enough time with healthcare provider (P=0.0058) correlated with poor control. CONCLUSIONS: A high percentage of US children with Type 1 diabetes had poor glycaemic control, especially those not using an insulin pump. Early identification of children with risk factors associated with poor glycaemic control within insulin regimens and addressing diabetes-related family conflict may allow interventions to improve diabetes management.


Assuntos
Diabetes Mellitus Tipo 1/prevenção & controle , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Adolescente , Glicemia/metabolismo , Criança , Diabetes Mellitus Tipo 1/epidemiologia , Feminino , Hemoglobinas Glicadas/metabolismo , Humanos , Masculino , Adesão à Medicação , Fatores de Risco , Fatores Socioeconômicos , Resultado do Tratamento , Estados Unidos/epidemiologia
6.
Diabet Med ; 35(4): 504-512, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29377258

RESUMO

AIM: To describe factors associated with transfer from paediatric to adult care and poor glycaemic control among young adults with Type 2 diabetes, using the SEARCH for Diabetes in Youth study. METHODS: Young adults with Type 2 diabetes were included if they had a baseline SEARCH visit while in paediatric care at < 18 years and ≥ 1 follow-up SEARCH visit thereafter at 18-25 years. At each visit, HbA1c , BMI, self-reported demographic and healthcare provider data were collected. Associations of demographic factors with transfer of care and poor glycaemic control (HbA1c ≥ 75 mmol/mol; 9.0%) were explored with multivariable logistic regression. RESULTS: 182 young adults with Type 2 diabetes (36% male, 75% minority, 87% with obesity) were included. Most (n = 102, 56%) reported transfer to adult care at follow-up; a substantial proportion (n = 28, 15%) reported no care and 29% did not transfer. Duration of diabetes [odds ratio (OR) 1.4, 95% confidence interval (95% CI) 1.1, 1.8] and age at diagnosis (OR 1.8, 95% CI 1.4, 2.4) predicted leaving paediatric care. Transfer to adult or no care was associated with a higher likelihood of poor glycaemic control at follow-up (adult: OR 4.5, 95% CI 1.8, 11.2; none: OR 4.6, 95% CI 1.4, 14.6), independent of sex, age, race/ethnicity or baseline HbA1c level. CONCLUSIONS: Young adults with Type 2 diabetes exhibit worsening glycaemic control and loss to follow-up during the transfer from paediatric to adult care. Our study highlights the need for development of tailored clinical programmes and healthcare system policies to support the growing population of young adults with youth-onset Type 2 diabetes.


Assuntos
Diabetes Mellitus Tipo 2/terapia , Transição para Assistência do Adulto/estatística & dados numéricos , Adolescente , Adulto , Distribuição por Idade , Idade de Início , Análise de Variância , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Feminino , Hemoglobinas Glicadas/metabolismo , Humanos , Cobertura do Seguro/estatística & dados numéricos , Seguro Saúde/estatística & dados numéricos , Masculino , Resultado do Tratamento , Adulto Jovem
7.
Rep Prog Phys ; 79(8): 084501, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27376888

RESUMO

We review the theory of mixed-valent metals and make comparison with experiments. A single-impurity description of the mixed-valent state is discussed alongside the description of the nearly-integer valent or Kondo limit. The degeneracy N of the f-shell plays an important role in the description of the low-temperature Fermi-liquid state. In particular, for large N, there is a rapid cross-over between the mixed-valent and the Kondo limit when the number of f electrons is changed. We discuss the limitations on the application of the single-impurity description to concentrated compounds such as those caused by the saturation of the Kondo effect and those due to the presence of magnetic interactions between the impurities. This discussion is followed by a description of a periodic lattice of mixed-valent ions, including the role of the degeneracy N. The article concludes with a comparison of theory and experiment. Topics covered include the single-impurity Anderson model, Luttinger's theorem, the Friedel sum rule, the Schrieffer-Wolff transformation, the single-impurity Kondo model, Kondo screening, the Wilson ratio, local Fermi-liquids, Fermi-liquid sum rules, the Noziéres exhaustion principle, Doniach's diagram, the Anderson lattice model, the Slave-Boson method, etc.

9.
Eur J Clin Nutr ; 70(7): 802-7, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26908421

RESUMO

BACKGROUND/OBJECTIVES: This study aimed to determine the association between a Mediterranean diet and glycemic control and other cardiovascular risk factors among youth with type I diabetes (TID). SUBJECTS/METHODS: Incident TID cases aged <20 years at diagnosis between 2002 and 2005 were included. Participants were seen at baseline (N=793), 1-year (N=512) and 5-year follow-up visits (N=501). Mediterranean diet score was assessed using a modified KIDMED index (mKIDMED). Multivariate linear regression and longitudinal mixed model were applied to determine the association between mKIDMED score and log-HbA1c, lipids, blood pressure (BP) and obesity. RESULTS: In cross-sectional analyses using baseline data, for individuals with the hemoglobin A1c (HbA1c) of 7.5%, a two-point higher mKIDMED score (1 s.d.) was associated with 0.15% lower HbA1c (P=0.02). A two-point higher mKIDMED score was associated with 4.0 mg/dl lower total cholesterol (TC) (P=0.006), 3.4 mg/dl lower low-density lipoprotein cholesterol (LDL-C) (P=0.004), 3.9 mg/dl lower non-high-density lipoprotein cholesterol (non-HDL-C) (P=0.004) and 0.07 lower LDL-C/HDL-C ratio (P=0.02). Using longitudinal data, a two-point increase in mKIDMED score was associated with 0.01% lower log-HbA1c (P=0.07), 1.8 mg/dl lower TC (P=0.05), 1.6 mg/dl lower LDL-C (P=0.03) and 1.8 mg/dl lower non-HDL-C (P=0.03) than would otherwise have been expected. HbA1c mediated ∼20% of the association for lipids in both cross-sectional and longitudinal models. An unexpected positive association between mKIDMED score and systolic BP was found among non-Hispanic white youth in cross-sectional analyses (P=0.009). Mediterranean diet was not associated with obesity. CONCLUSIONS: Mediterranean diet may improve glycemic control and cardiovascular health in TID youth.


Assuntos
Glicemia/metabolismo , Doenças Cardiovasculares/sangue , Diabetes Mellitus Tipo 1/dietoterapia , Dieta Mediterrânea , Comportamento Alimentar , Hemoglobinas Glicadas/metabolismo , Lipídeos/sangue , Adolescente , Adulto , Pressão Sanguínea , Doenças Cardiovasculares/etiologia , Criança , Pré-Escolar , Estudos Transversais , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/tratamento farmacológico , Feminino , Seguimentos , Humanos , Insulina/uso terapêutico , Lipoproteínas/sangue , Masculino , Obesidade , Cooperação do Paciente , Fatores de Risco , População Branca , Adulto Jovem
10.
J Phys Condens Matter ; 27(1): 015602, 2015 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-25469766

RESUMO

Electric resistivity, specific heat, magnetic susceptibility, and inelastic neutron scattering experiments were performed on a single crystal of the heavy fermion compound Ce(Ni0.935Pd0.065)2Ge2 in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). The resistivity and the specific heat coefficient for T ⩽ 1 K exhibit the power law behavior expected for a 3D itinerant AF QCP (ρ(T) ∼ T(3/2) and γ(T) ∼ γ0 - bT(1/2)). However, for 2 ⩽ T ⩽ 10 K, the susceptibility and specific heat vary as log T and the resistivity varies linearly with temperature. Furthermore, despite the fact that the resistivity and specific heat exhibit the non-Fermi liquid behavior expected at a QCP, the correlation length, correlation time, and staggered susceptibility of the spin fluctuations remain finite at low temperature. We suggest that these deviations from the divergent behavior expected for a QCP may result from alloy disorder.

11.
J Phys Condens Matter ; 26(22): 225602, 2014 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-24824417

RESUMO

We report inelastic neutron scattering experiments on a single crystal of the intermediate valence compound CePd3. At 300 K the magnetic scattering is quasielastic, with half-width Γ = 23 meV, and is independent of momentum transfer Q. At low temperature, the Q-averaged magnetic spectrum is inelastic, exhibiting a broad peak centered near Emax = 55 meV. These results, together with the temperature dependence of the susceptibility, 4f occupation number, and specific heat, can be fit by the Kondo/Anderson impurity model. The low temperature scattering near Emax, however, shows significant variations with Q, reflecting the coherence of the 4f lattice. The intensity is maximal at (1/2, 1/2, 0), intermediate at (1/2, 0, 0) and (0, 0, 0), and weak at (1/2, 1/2, 1/2). We discuss this Q-dependence in terms of current ideas about coherence in heavy fermion systems.


Assuntos
Cério/química , Modelos Químicos , Paládio/química , Simulação por Computador , Campos Magnéticos , Marcadores de Spin , Temperatura
12.
Diabet Med ; 30(11): 1324-32, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23909945

RESUMO

AIMS: To determine the prevalence of plasma vitamin D (25-dihydroxyvitamin D) insufficiency in individuals with Type 1 diabetes and to determine the cross-sectional and longitudinal associations of plasma vitamin D with insulin resistance. METHODS: Participants from the SEARCH for Diabetes in Youth Study [n = 1426; mean age 11.2 years (sd 3.9)] had physician-diagnosed Type 1 diabetes [diabetes duration mean 10.2 months (sd 6.5)] with data available at baseline and follow-up (approximately 12 and 24 months after baseline). Insulin resistance was estimated using a validated equation. Cross-sectional and longitudinal multivariate logistic regression models were used to determine the association of plasma vitamin D with insulin resistance, adjusting for potential confounders. RESULTS: Forty-nine per cent of individuals had plasma vitamin D < 50 nmol/l and 26% were insulin resistant. In cross-sectional multivariate analyses, participants who had higher plasma vitamin D (65 nmol/l) had lower odds of prevalent insulin resistance than participants with lower plasma vitamin D (25 nmol/l) (odds ratio 0.70, 95% CI 0.57-0.85). This association was attenuated after additional adjustment for BMI z-score, which could be a confounder or a mediator (odds ratio 0.81, 95% CI 0.64-1.03). In longitudinal multivariate analyses, individuals with higher plasma vitamin D at baseline had lower odds of incident insulin resistance, but this was not significant (odds ratio 0.85, 95% CI 0.63-1.14). CONCLUSIONS: Vitamin D insufficiency is common in individuals with Type 1 diabetes and may increase risk for insulin resistance. Additional prospective studies are needed to determine the association between plasma vitamin D and insulin resistance, and to further examine the role of adiposity on this association.


Assuntos
Diabetes Mellitus Tipo 1/etiologia , Deficiência de Vitamina D/complicações , Vitamina D/análogos & derivados , Adolescente , Criança , Métodos Epidemiológicos , Feminino , Humanos , Resistência à Insulina/fisiologia , Masculino , Vitamina D/sangue , Adulto Jovem
13.
Diabet Med ; 29(9): 1148-52, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22269205

RESUMO

AIMS: The aim of this pilot study was to generate an initial estimate of the prevalence and correlates of diabetic retinopathy in a racially and ethnically diverse sample of youth with Type 1 and Type 2 diabetes mellitus. METHODS: A pilot study was conducted among 222 individuals with Type 1 diabetes (79% non-Hispanic white, 21% other) and 43 with Type 2 diabetes (28% non-Hispanic white, 72% other), all of > 5 years duration (mean duration 6.8 years) who participated in the SEARCH for Diabetes in Youth study. Diabetic retinopathy was assessed using non-mydriatic retinal photography of both eyes. RESULTS: The prevalence of diabetic retinopathy was 17% for Type 1 diabetes and 42% for Type 2 diabetes (odds ratio 1.50, 95% CI 0.58-3.88; P = 0.40 adjusted for age, duration, gender, race/ethnicity, parental education and HbA(1c). HbA(1c) was significantly higher among those with any diabetic retinopathy (adjusted mean 79 mmol/mol, 9.4%) vs. no diabetic retinopathy (adjusted mean 70 mmol/mol, 8.6%) (P = 0.015). LDL cholesterol was also significantly higher among those with any diabetic retinopathy (adjusted mean 107.2 mg/dl) compared with those without diabetic retinopathy (adjusted mean 97.9 mg/dl) (P = 0.04). CONCLUSIONS: The prevalence of diabetic retinopathy in contemporary young individuals was substantial, particularly among minority youth and those with Type 2 diabetes. Further long-term study of diabetic retinopathy in youth is needed.


Assuntos
Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 2/complicações , Retinopatia Diabética/epidemiologia , Adolescente , Criança , Estudos de Coortes , Diabetes Mellitus Tipo 1/etnologia , Diabetes Mellitus Tipo 2/etnologia , Retinopatia Diabética/etnologia , Humanos , Grupos Minoritários , Projetos Piloto , Prevalência , Estados Unidos/epidemiologia , População Branca/etnologia , Adulto Jovem
14.
Diabetologia ; 54(12): 3016-21, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22016046

RESUMO

AIMS/HYPOTHESIS: To investigate racial/ethnic disparities in diabetes risk after gestational diabetes mellitus (GDM). METHODS: This is a retrospective cohort study of women enrolled in the Kaiser Permanente Southern California health plan from 1995 to 2009. GDM status was identified on the basis of plasma glucose levels during pregnancy. The incidence of diabetes after the first delivery complicated by GDM before 31 December 2009 (n = 12,998) was compared with the experience for women without GDM (n = 64,668) matched on maternal age at delivery, race/ethnicity and year of delivery (1:5 ratio). Matched Cox regression was used to compare the RRs of diabetes associated with GDM within and across racial/ethnic groups. RESULTS: Compared with the women without GDM, the HRs (95% CI) of diabetes for women after GDM were 6.5 (5.2, 8.0) in non-Hispanic white, 7.7 (6.8, 8.7) in Hispanic, 9.9 (7.5, 13.1) in black and 6.3 (5.0, 7.9) in Asian/Pacific Islanders after adjustment for parity, maternal education, comorbidity and number of outpatient visits before the index pregnancy. The HR of diabetes for black women was significantly higher than that for non-Hispanic white women (p = 0.032). Further adjustment for prepregnancy BMI reduced the diabetes risk association with GDM for each racial/ethnic group, but did not explain the risk differences across groups. CONCLUSIONS/INTERPRETATIONS: Racial/ethnic disparities exist in risk of diabetes after GDM. Black women with GDM had the highest risk of developing diabetes. This highlights the importance of developing an effective diabetes screening and prevention programme in women with GDM, particularly black women with GDM.


Assuntos
Diabetes Mellitus/epidemiologia , Diabetes Gestacional/epidemiologia , Disparidades nos Níveis de Saúde , Adulto , População Negra/estatística & dados numéricos , California , Diabetes Mellitus/etnologia , Diabetes Mellitus/etiologia , Diabetes Gestacional/etnologia , Diabetes Gestacional/fisiopatologia , Feminino , Seguimentos , Hispânico ou Latino/estatística & dados numéricos , Humanos , Incidência , Masculino , Gravidez , Prevalência , Estudos Retrospectivos , Risco , População Branca/estatística & dados numéricos
15.
J Phys Condens Matter ; 23(9): 094210, 2011 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-21339563

RESUMO

In an effort to explore the differences between rare-earth-based and uranium-based heavy fermion (HF) compounds that reflect the underlying difference between local 4f moments and itinerant 5f moments we analyze scaling laws that relate the low temperature neutron spectra of the primary ('Kondo-esque') spin fluctuation to the specific heat and susceptibility. While the scaling appears to work very well for the rare earth intermediate valence (IV) compounds, for a number of key uranium compounds the scaling laws fail badly. There are two main reasons for this failure. First, the presence of antiferromagnetic (AF) fluctuations, which contribute significantly to the specific heat, alters the scaling ratios. Second, the scaling laws require knowledge of the high temperature moment degeneracy, which is often undetermined for itinerant 5f electrons. By making plausible corrections for both effects, better scaling ratios are obtained for some uranium compounds. We point out that, while both the uranium HF compounds and the rare earth IV compounds have spin fluctuation characteristic energies of order 5-25 meV, they differ in that the AF fluctuations that are usually seen in the uranium compounds are never seen in the rare earth IV compounds. This suggests that the 5f itineracy increases the f-f exchange relative to the rare earth case.

16.
Diabetologia ; 54(3): 535-9, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21109996

RESUMO

AIM/HYPOTHESIS: Common variants in the transcription factor 7-like 2 (TCF7L2) gene have been associated with type 2 diabetes in adults. However, it is not known whether TCF7L2 variation increases the risk of early onset type 2 diabetes. Using a case-control design, we examined whether the reported variants [rs12255372 (T/G) and rs7903146 (T/C)] are associated with type 2 diabetes in SEARCH for Diabetes in Youth study participants. METHODS: Variants were genotyped in 694 non-Hispanic white (NHW) youth (86 cases, mean age 15.5 years, mean BMI 34.8; and 608 controls, mean age 14.4 years, mean BMI 22.3) and 545 African-American (AA) youth (154 cases, mean age 15.9, mean BMI 37; and 391 controls, mean age 14.8, mean BMI 23.8). Logistic regression adjusted for age, sex, BMI and West African ancestry. RESULTS: The association of the risk T allele with case/control status was different in AA and NHW youth (p = 0.025). Among AA youth, each copy of the T allele (rs7903146) was associated with a 1.97-fold (1.37, 2.82) increased odds for type 2 diabetes (p < 0.0001), after adjustment for age, sex, BMI and African ancestry. No significant association was detected in NHW youth (adjusted OR, 1.14; 0.73, 1.79). CONCLUSION/INTERPRETATION: TCF7L2 variation is associated with an increased risk of early-onset type 2 diabetes among AA youth, and the association appears to be stronger in AA than NHW youth. This suggests potential different contributions of genetic and environmental factors to early-onset type 2 diabetes by race.


Assuntos
Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/genética , Polimorfismo Genético/genética , Proteína 2 Semelhante ao Fator 7 de Transcrição/genética , Adolescente , Diabetes Mellitus Tipo 2/etnologia , Feminino , Predisposição Genética para Doença , Humanos , Masculino
17.
Bone Marrow Transplant ; 46(5): 682-9, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-20697372

RESUMO

Patients undergoing auto-SCT for neuroblastoma present a unique population to study transplant-associated thrombotic microangiopathy (TA-TMA), due to standardized chemotherapy and later exposure to radiation and cis-retinoic acid (cis-RA). We retrospectively analyzed 20 patients after auto-SCT to evaluate early clinical indicators of TA-TMA. A total of 6 patients developing TA-TMA (30% prevalence) were compared with 14 controls. Four of six patients were diagnosed with TA-TMA by 25 days after auto-SCT. Compared with controls, TA-TMA patients had higher average systolic and diastolic blood pressure levels during high-dose chemotherapy and developed hypertension by day 13 after auto-SCT. Proteinuria was a significant marker for TA-TMA, whereas blood and platelet transfusion requirements were not. Serum creatinine did not differ between groups post transplant. However, patients with TA-TMA had a 60% decrease in renal function from baseline by nuclear glomerular filtration rate, compared with a 25% decrease in those without TA-TMA (P=0.001). There was no TA-TMA-related mortality. Significant complications included end-stage renal disease (n=1) and polyserositis (n=3). Patients with TA-TMA were unable to complete cis-RA therapy after auto-SCT. We suggest that careful attention to blood pressure and urinalysis will assist in the early diagnosis of TA-TMA, whereas serum creatinine seems to be an insensitive marker for this condition.


Assuntos
Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Neuroblastoma/cirurgia , Microangiopatias Trombóticas/diagnóstico , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea , Estudos de Casos e Controles , Pré-Escolar , Feminino , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/etiologia , Masculino , Proteinúria/etiologia , Estudos Retrospectivos , Microangiopatias Trombóticas/complicações , Microangiopatias Trombóticas/etiologia , Condicionamento Pré-Transplante , Transplante Autólogo
18.
Phys Rev Lett ; 104(17): 176402, 2010 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-20482120

RESUMO

We present a neutron scattering investigation of Ce1-xYxAl3 as a function of chemical pressure, which induces a transition from heavy-fermion behavior in CeAl3 (T{K}=5 K) to a mixed-valence state at x=0.5 (T{K}=150 K). The crossover can be modeled accurately on an absolute intensity scale by an increase in the k-f hybridization, V{kf}, within the Anderson impurity model. Surprisingly, the principal effect of the increasing V{kf} is not to broaden the low-energy components of the dynamic magnetic susceptibility but to transfer spectral weight to high energy.

19.
Exp Eye Res ; 90(2): 308-15, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19961848

RESUMO

Retinal ganglion cell (RGC) death in glaucoma models is associated with accumulation of activated microglia, a sign of neural degeneration which has been shown to constitute a barrier for transplant cell survival and migration. This study investigated the use of triamcinolone (TA) to control macrophage/microglia accumulation in a model of RGC depletion to create a permissive environment for stem cell grafting. Intravitreal NMDA alone or in combination with TA was used to induce rapid onset of RGC death in 3-4 week old Lister hooded (LH) rat eyes prior to Müller stem cell transplantation into the vitreoretinal space. The effect of NMDA on RGC death and microglial accumulation was assessed immuno-histochemically, whilst electroretinography (ERG) was used to assess RGC function. Post transplantation, survival of grafted cells and their association with microglia were also examined by immunohistochemical methods. Intravitreal injection of NMDA alone resulted in severe macrophage/microglia accumulation associated with extensive RGC death 4-7 days post-treatment. Combination of NMDA with TA significantly reduced microglial numbers in the RGC when compared to NMDA only treated eyes while still depleting the retina of RGC. At the same time, NMDA/TA treatment also caused functional RGC loss as demonstrated by reduction of the scotopic threshold response. Upon transplantation with Müller stem cells, NMDA/TA treatment caused significant reduction in the number of transplant associated macrophage/microglia compared to eyes treated with NMDA alone. On this basis it is proposed that intravitreal injection of TA may be useful as an effective anti-inflammatory agent to control macrophage/microglia accumulation induced by RGC death, thereby creating a retinal environment permissive to cell transplantation studies.


Assuntos
Anti-Inflamatórios/farmacologia , Sobrevivência de Enxerto/fisiologia , Macrófagos/metabolismo , Microglia/metabolismo , N-Metilaspartato/toxicidade , Células Ganglionares da Retina/patologia , Transplante de Células-Tronco , Triancinolona Acetonida/farmacologia , Animais , Apoptose/efeitos dos fármacos , Biomarcadores/metabolismo , Sobrevivência Celular , Eletrorretinografia , Técnica Indireta de Fluorescência para Anticorpo , Hibridização in Situ Fluorescente , Marcação In Situ das Extremidades Cortadas , Injeções , Microglia/citologia , Ratos , Células Ganglionares da Retina/metabolismo , Corpo Vítreo
20.
J Hum Nutr Diet ; 20(4): 311-9, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17635308

RESUMO

BACKGROUND: Lower birth weight, often found in infants from minority ethnic groups, may be partly because of the disproportionate representation of ethnic minority groups in low-income areas. To develop an intervention, to improve the nutritional intake of young women from populations at risk of low-birth-weight babies, which would be culturally sensitive and well received by the intended recipients, a community development approach was used to investigate factors that might influence food choice and the nutritional intake of girls and young women from ethnic minority groups. METHODS: Focus group discussions were conducted across the UK, to explore factors that might affect the food choices of girls and young women of African and South Asian decent. The data was analysed using deductive content analysis (Qual. Soc. Res., 1, 2000, 1). Discussions were around the broad themes of buying and preparing food, eating food and dietary changes, and ideas for an intervention to improve diet. RESULTS: The focus group discussions indicated that all the communities took time, price, health and availability into consideration when making food purchases. The groups were also quite similar in their use of 'Western' foods which tended to be of the fast food variety. These foods were used when there was not enough time to prepare a 'traditional' meal. CONCLUSION: Many issues that affect the food choice of people who move to the UK are common within different ethnic groups. The idea of a practical intervention based on improving cooking skills was popular with all the groups.


Assuntos
Comportamento de Escolha , Culinária/métodos , Etnicidade/psicologia , Grupos Minoritários/psicologia , Ciências da Nutrição/educação , Aculturação , Adolescente , Adulto , Atitude Frente a Saúde , Criança , Etnicidade/educação , Feminino , Grupos Focais , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Grupos Minoritários/educação , Fatores Socioeconômicos , Reino Unido
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