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1.
Placenta ; 128: 9-17, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36037665

RESUMO

INTRODUCTION: Despite the acknowledgement that physical activity is beneficial during pregnancy and may result in positive health outcomes for the newborn child few studies have examined this issue. This research was deemed necessary with the primary objective of identifying possible associations between adherence to American College of Sports Medicine recommendations on neonatal outcome variables at birth. METHODS: An observational, longitudinal and prospective study focused on a sample of 70 pregnant women (the power score achieved was estimated to be 0.3). Data was collected in three stages (1st and 2nd trimester of pregnancy and 48 h after delivery). The variables analyzed included the physical activity measurement (with accelerometry), neonatal outcomes at birth and the mother's anxiety, dietary intake, anthropometric measures and socio-demographic and lifestyle. RESULTS: 21.4% women were active according to physical activity recommendations. There were no significant differences in neonatal outcomes at birth when comparing adherence to physical activity recommendations and the overall activity levels of the mothers. There were also no statistically significant differences in the birth weights of babies born to active and inactive mothers. Mother's anxiety level, weight gained and dietary intake were not statistically different according to compliance with physical activity behaviour or recommendations. DISCUSSION: There is no relationship between adherence to physical activity recommendations on neonatal outcome variables at birth. There were also no significant associations with sociodemographic and lifestyle variables. There is a need to identify attitudes associated with negative physical activity behavior to reduce the incidence of comorbidities associated with sedentary lifestyles during pregnancy.


Assuntos
Complicações na Gravidez , Resultado da Gravidez , Peso ao Nascer , Exercício Físico , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Gravidez , Complicações na Gravidez/etiologia , Resultado da Gravidez/epidemiologia , Estudos Prospectivos
2.
Phys Chem Chem Phys ; 24(24): 14886-14897, 2022 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-35674089

RESUMO

The importance of choline chloride (ChCl) is recognized due to its widespread use in the formulation of deep eutectic solvents. The controlled addition of water in deep eutectic solvents has been proposed to overcome some of the major drawbacks of these solvents, namely their high hygroscopicities and viscosities. Recently, aqueous solutions of ChCl at specific mole ratios have been presented as a novel, low viscous deep eutectic solvent. Nevertheless, these proposals are suggested without any information about the solid-liquid phase diagram of this system or the deviations from the thermodynamic ideality of its precursors. This work contributes significantly to this matter as the phase behavior of pure ChCl and (ChCl + H2O) binary mixtures was investigated by calorimetric and analytical techniques. The thermal behavior and stability of ChCl were studied by polarized light optical microscopy and differential scanning calorimetry, confirming the existence of a solid-solid transition at 352.2 ± 0.6 K. Additionally, heat capacity measurements of pure ChCl (covering both ChCl solid phases) and aqueous solutions of ChCl (xChCl < 0.4) were performed using a heat-flow differential scanning microcalorimeter or a high-precision heat capacity drop calorimeter, allowing the estimation of a heat capacity change of (ChCl) ≈ 39.3 ± 10 J K-1 mol-1, between the hypothetical liquid and the observed crystalline phase at 298.15 K. The solid-liquid phase diagram of the ChCl + water mixture was investigated in the whole concentration range by differential scanning calorimetry and the analytical shake-flask method. The phase diagram obtained for the mixture shows an eutectic temperature of 204 K, at a mole fraction of choline chloride close to xChCl = 0.2, and a shift of the solid-solid transition of ChCl-water mixtures of 10 K below the value observed for pure choline chloride, suggesting the appearance of a new crystalline structure of ChCl in the presence of water, as confirmed by X-ray diffraction. The liquid phase presents significant negative deviations to ideality for water while COSMO-RS predicts a near ideal behaviour for ChCl.

3.
J Frailty Sarcopenia Falls ; 5(2): 42-46, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32510030

RESUMO

MOVE.TE is a non-profit participatory physiotherapy platform that aims at translating knowledge in the field of physiotherapy and developing freely available evidence-based physiotherapy programmes targeting the primary care services of the Portuguese National Health service. A group of volunteer academics and clinicians collaborated at different stages and time points to create the first ever falls prevention and management programme and guidance for Physiotherapy in primary care, in Portugal. This report describes this seven-step process. In spite of many challenges, this project constitutes an example of advocacy in physiotherapy for the promotion of better healthcare for older adults.

4.
Obes Res Clin Pract ; 11(3): 276-286, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27473300

RESUMO

BACKGROUND: The role played by dairy product intake during pregnancy on neonatal outcomes has raised interest in the last few years. However, studies on this association remain scarce. Thus, the aim of this study was to determine the association between dairy product consumption during pregnancy and neonatal and maternal outcomes. METHODS: A prospective study was conducted with 98 pregnant women, aged 18-40, from the city of Porto, Portugal. Socio-demographic and lifestyle characteristics were assessed through a questionnaire. Dairy product consumption was assessed with a three-day food diary completed during the first and second trimesters. Postpartum medical records were examined for neonatal and maternal outcomes. Multivariate linear regression analyses were performed to assess the association between dairy intake and neonatal and maternal outcomes, adjusting for dietary variables and maternal characteristics. RESULTS: Compared to the first trimester pregnant women had higher energy intake and lower calcium, iodine and yogurt intake in the second trimester (P<0.05). Total dairy and yogurt intake in the first trimester were positively associated with head circumference and placental weight (respectively ß=0.002, P=0.014, ß=0.333, P=0.012). Change in total dairy intake between the second and first trimester was negatively associated with maternal weight gain during pregnancy (ß=-0.007, P=0.020). CONCLUSION: The findings of this study suggest that dairy product intake during pregnancy may have an effect on neonatal head circumference, placental weight, and gestational weight gain.


Assuntos
Laticínios , Dieta , Fenômenos Fisiológicos da Nutrição Materna/fisiologia , Resultado da Gravidez , Adolescente , Adulto , Registros de Dieta , Feminino , Humanos , Estilo de Vida , Portugal , Gravidez , Estudos Prospectivos , Adulto Jovem
5.
Rev. bras. farmacogn ; 26(4): 446-450, July-Aug. 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-792696

RESUMO

ABSTRACT This study assessed the protective effect of the carotenoid bixin and annatto seeds against possible nephrotoxicity induced with a single peritoneal administration of pharmacological cisplatin in male Wistar rats. After 48 h, the blood cell differential count showed a significant reduction in neutrophil counts in rats that received a diet rich in bixin when compared to the group that received only cisplatin. The use of cisplatin led to an increase in kidney weight. The carotenoid bixin attenuated renal injury, characterized by increased polymorphonuclear infiltration. No protective effect was observed with respect to Annatto. These results demonstrate the role of toxic cisplatin and suggest that bixin affords a protective effect against cisplatin-induced nephrotoxicity in adult Wistar rats.

6.
Neurol Res ; 38(10): 851-6, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27426639

RESUMO

OBJECTIVE: The main aim of this study was to identify the prognostic factors that contribute to complete recovery at 6 weeks and 6 months in patients with Bell's palsy. MATERIAL AND METHODS: This is a prospective, longitudinal, and descriptive study that included 123 patients diagnosed with facial nerve palsy (FNP) at a hospital in Guimarães, Portugal. However, only 73 patients with Bell's palsy (BP) were included in the assessment of recovery at 6 weeks and 6 months. We analyzed the demographic and clinical characteristics of the patients, including sex, age, paralyzed side, occupation, previous and associated symptoms, seasonal occurrence, familial facial palsy, patient perception, intervention options, and baseline grade according to the House-Brackmann facial grading system (HB-FGS). RESULTS: Of the 123 cases with FNP, 79 (64.2%) patients had BP. Age, sex, and baseline HB-FGS grades were significant predictors of complete recovery at 6 weeks. Patients with HB-FGS grade III or lower (6 weeks baseline) had significant recovery of function at 6 months. CONCLUSIONS: Baseline severity of BP, elderly patients, and male sex were early predictors of poor prognosis. Patients with mild and moderate dysfunction according to the HB-FGS achieved significant normal facial function at 6 months. Further prospective studies with longer observation periods and larger samples are needed to verify the results.


Assuntos
Paralisia de Bell/diagnóstico , Paralisia de Bell/epidemiologia , Recuperação de Função Fisiológica/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Diagnóstico Diferencial , Paralisia Facial/diagnóstico , Feminino , Humanos , Incidência , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Portugal/epidemiologia , Prognóstico , Curva ROC , Estudos Retrospectivos , Índice de Gravidade de Doença , Adulto Jovem
7.
Acta Otolaryngol ; 136(7): 736-41, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27003272

RESUMO

Conclusions The results provide preliminary evidence that corticosteroids were not effective in all grades of dysfunction and for achieving a rapid remission in the early phase of BP, highlighting the need to define standard and rigorous criteria to prescribe corticosteroids in these patients. Objectives The main aim of this study was to investigate whether the use of corticosteroids better associated than paralleled with neuromuscular training (C + FNT) is more effective than facial neuromuscular training (FNT) applied alone, in terms of recovery degree and facial symmetry during the early phase of Bell's palsy (BP). Patients and methods A prospective single-blinded study involved 73 patients: the C + FNT group (n = 42; median age = 37.5 years) and FNT group (n = 31; median age = 49.0 years). Patients were assessed before and 6 weeks after treatment by House-Brackmann (HB-FGS) and Sunnybrook Facial Grading System (SB-FGS). Results Recovery degree and facial symmetry improved significantly in both groups (p < 0.001), without differences between groups (p > 0.05). However, the C + FNT group displayed better outcomes for cheek (p = 0.004) and mouth (p = 0.022) resting symmetry at SB-FGS, instead of compared to the FNT group. The corticosteroids had no significant effect on all recovery degrees (p = 0.992) and rapid remission (p = 0.952). Multiple linear regression analysis showed that the type of intervention was not a significant predictor for recovery degree (p = 0.917).


Assuntos
Corticosteroides/uso terapêutico , Paralisia de Bell/tratamento farmacológico , Adulto , Paralisia de Bell/reabilitação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modalidades de Fisioterapia , Estudos Prospectivos
8.
Eur Neuropsychopharmacol ; 25(6): 913-22, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25840741

RESUMO

A wealth of evidence implicates the BDNF-TRKB system in the therapeutic effects of antidepressant drugs (ADs) on mood disorders. However, little is known about the involvement of this system in the panicolytic property also exerted by these compounds. In the present study we evaluated the participation of the BDNF-TRKB system of the dorsal periaqueductal gray matter (DPAG), a core structure involved in the pathophysiology of panic disorder, in AD-induced panicolytic-like effects in rats. The results showed that short- (3 days) or long-term (21 days) systemic treatment with the tricyclic ADs imipramine, clomipramine or desipramine increased BDNF levels in the DPAG. Only longterm treatment with the selective serotonin reuptake inhibitor fluoxetine was able to increase BDNF levels in this structure. After 21-day treatment, fluoxetine and the three tricyclic ADs used also increased BDNF concentration in the hippocampus, a key area implicated in their mood-related actions. Neither in the DPAG nor hippocampus did long-term treatment with the standard anxiolytics diazepam, clonazepam or buspirone affect BDNF levels. Imipramine, both after short and long-term administration, and fluoxetine under the latter regimen, raised the levels of phosphorylated TRKB in the DPAG. Short-term treatment with imipramine or BDNF microinjection inhibited escape expression in rats exposed to the elevated T maze, considered as a panicolytic-like effect. This anti-escape effect was attenuated by the intra-DPAG administration of the TRK receptor antagonist k252a. Altogether, our data suggests that facilitation of the BDNF-TRKB system in the DPAG is implicated in the panicolytic effect of ADs.


Assuntos
Antidepressivos/farmacologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Substância Cinzenta Periaquedutal/efeitos dos fármacos , Substância Cinzenta Periaquedutal/metabolismo , Receptor trkB/metabolismo , Transdução de Sinais/efeitos dos fármacos , Análise de Variância , Animais , Ansiolíticos/farmacologia , Carbazóis/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Reação de Fuga/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Alcaloides Indólicos/farmacologia , Injeções Intra-Articulares , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Ratos , Ratos Wistar , Tempo de Reação/efeitos dos fármacos , Fatores de Tempo
9.
Am J Phys Med Rehabil ; 94(4): 331-40, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25785922

RESUMO

The physical therapy (PT) associated with standard drug treatment (SDT) in Bell palsy has never been investigated. Randomized controlled trials or quasirandomized controlled trials have compared facial PT (except treatments such as acupuncture and osteopathic) combined with SDT against a control group with SDT alone. Participants included those older than 15 yrs with a clinical diagnosis of Bell palsy, and the primary outcome measure was motor function recovery by the House-Brackmann scale. The methodologic quality of each study was also independently assessed by two reviewers using the PEDro scale. Four studies met the inclusion criteria. Three trials indicate that PT in association with SDT supports higher motor function recovery than SDT alone between 15 days and 1 yr of follow-up. On the other hand, one trial showed that electrical stimulation added to conventional PT with SDT did not influence treatment outcomes. The present review suggests that the current practice of Bell palsy treatment by PT associated with SDT seems to have a positive effect on grade and time recovery compared with SDT alone. However, there is very little quality evidence from randomized controlled trials, and such evidence is insufficient to decide whether combined treatment is beneficial in the management of Bell palsy.


Assuntos
Paralisia de Bell/reabilitação , Modalidades de Fisioterapia , Paralisia de Bell/tratamento farmacológico , Terapia Combinada , Terapia por Estimulação Elétrica , Músculos Faciais , Humanos , Reprodutibilidade dos Testes , Resultado do Tratamento
10.
Metab Syndr Relat Disord ; 12(3): 171-7, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24495166

RESUMO

BACKGROUND: A growing body of research suggests that vitamin D might play an important role in overall health. No data exist on vitamin D intake for the Azorean adolescent population. The purpose of this study was to assess vitamin D intake and investigate a possible association between vitamin D intake and cardiometabolic risk factors in Azorean adolescents. METHODS: A cross-sectional school-based study was conducted on 496 adolescents (288 girls) aged 15-18 years from the Azorean Islands, Portugal. Anthropometric measurements (waist circumference and height), blood pressure (systolic), and plasma biomarkers [fasting glucose, insulin, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs)] were measured to assess metabolic risk. Homeostasis model assessment (HOMA), TC-to-HDL-C ratio, and waist-to-height ratio were calculated. For each of these variables, a Z-score was computed by age and sex. A metabolic risk score was constructed by summing the Z-scores of all individual risk factors. High risk was considered when the individual had ≥1 standard deviation (SD) of this score. Vitamin D intake was assessed with a semiquantitative food frequency questionnaire. Participants were classified into quartiles of vitamin D intake. Logistic regression was used to determine odds ratios for high cardiometabolic risk scores after adjusting for total energy intake, pubertal stage, fat mass percentage, and cardiorespiratory fitness. RESULTS: Mean (SD) vitamin D intake was 5.8 (6.5) µg/day, and 9.1% of Azorean adolescents achieved the estimated average requirement of vitamin D (10 µg/day or 400 IU). Logistic regression showed that the odds ratio for a high cardiometabolic risk score was 3.35 [95% confidence interval (CI) 1.28-8.75] for adolescents in the lowest vitamin D intake quartile in comparison with those in the highest vitamin D intake quartile, even after adjustment for confounders. CONCLUSION: A lower level of vitamin D intake was associated with worse metabolic profile among Azorean adolescents.


Assuntos
Doenças Cardiovasculares/epidemiologia , Doenças Metabólicas/epidemiologia , Vitamina D/administração & dosagem , Vitaminas/administração & dosagem , Adolescente , Antropometria , Açores/epidemiologia , Pressão Sanguínea/fisiologia , Dieta , Feminino , Humanos , Estudos Longitudinais , Masculino , Atividade Motora , Aptidão Física , Puberdade/fisiologia , Fatores de Risco , Caracteres Sexuais
11.
Public Health Nutr ; 15(1): 13-9, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21899788

RESUMO

OBJECTIVE: There are no percentile curves for BMI, waist circumference (WC) or waist-to-height ratio (WHtR) available for Portuguese children and adolescents. The purpose of the present study was to develop age- and sex-specific BMI, WC and WHtR percentile curves for a representative sample of adolescents living in the Portuguese islands of Azores, one of the poorest regions of Europe, and to compare them with those from other countries. DESIGN: Cross-sectional school-based study. Weight, height and WC were objectively measured according to standard procedures. Smoothed percentile curves were estimated using Cole's LMS method. SETTING: Azores, Portugal. SUBJECTS: Proportionate stratified random sample of 1500 adolescents, aged 15-18 years. RESULTS: Results showed some sex differences in the shape of the BMI curves: in girls, the upper percentile values tend to decrease by the age of 16 and 17 years; whereas in boys, the upper percentiles tend to be flat between 15 and 16 years and then increase until the age of 18 years. In both sexes, the upper percentile values of both WC and WHtR decreased slightly by the age of 16 years and then increased steeply. In both sexes, the Azorean values for the 50th and 90th WC percentiles were higher than those reported for adolescents from the majority of other countries. CONCLUSIONS: The reference curves presented herein provide baseline data for the long-term surveillance of Azorean adolescents, as well as for national and international comparisons.


Assuntos
Estatura , Índice de Massa Corporal , Peso Corporal , Obesidade/epidemiologia , Circunferência da Cintura , Adolescente , Fatores Etários , Açores/epidemiologia , Estudos Transversais , Feminino , Humanos , Masculino , Prevalência , Valores de Referência , Fatores de Risco , Instituições Acadêmicas , Fatores Sexuais
12.
J Obes ; 2011: 578106, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21792387

RESUMO

Introduction. This study aimed to evaluate the screening performance of different measures of adiposity: body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) for high metabolic risk in a sample of adolescents. Methods. A cross-sectional school-based study was conducted on 517 adolescents aged 15-18, from the Azorean Islands, Portugal. We measured fasting glucose, insulin, total cholesterol (TC), HDL-cholesterol, triglycerides, and systolic blood pressure. HOMA and TC/HDL-C ratio were calculated. For each of these variables, a Z-score was computed by age and sex. A metabolic risk score (MRS) was constructed by summing the Z-scores of all individual risk factors. High risk was considered when the individual had ≥1SD of this score. Receiver-operating characteristics (ROC) were used. Results. Linear regression analyses showed that, after adjusting for age and pubertal stage, all different measures of adiposity are positively and significantly associated with MRS in both sexes, with exception of WHtR for boys. BMI, WC, and WHtR performed well in detecting high MRS, indicated by areas under the curve (AUC), with slightly greater AUC for BMI than for WC and WHtR in both sexes. Conclusion. All measures of adiposity were significantly associated with metabolic risk factors in a sample of Portuguese adolescents.

13.
BMC Public Health ; 11: 214, 2011 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-21470414

RESUMO

BACKGROUND: The prevalence of metabolic syndrome has increased over the last few decades in adolescents and has become an important health challenge worldwide. This study analyzed the relationships between metabolic risk factors (MRF) and physical activity (PA) and physical fitness (PF) in a sample of Azorean adolescents. METHODS: A cross-sectional school-based study was conducted on 417 adolescents (243 girls) aged 15-18 from the Azorean Islands, Portugal. Height, weight, waist circumference, fasting glucose, HDL-cholesterol, triglycerides, and blood pressure were measured. A sum of MRF was computed, and adolescents were classified into three groups: no MRF, one MRF and two or more MRF. PA was assessed by a sealed pedometer. PF was assessed using five tests from the Fitnessgram Test Battery. Dietary intake was obtained using a semi-quantitative food frequency questionnaire. RESULTS: Mean daily steps for girls and boys were 7427 ± 2725 and 7916 ± 3936, respectively. Fifty-nine percent of the adolescents showed at least one MRF and 57.6% were under the healthy zone in the 20 m Shuttle Run Test. Ordinal logistic regression analysis showed that after adjusting for sex, body mass index, socio-economic status and adherence to a Mediterranean diet, adolescents who were in the highest quartile of the pedometer step/counts (≥9423 steps/day) and those who achieved the healthy zone in five tests were less likely to have one or more MRF (OR = 0.56;95%CI:0.33-0.95; OR = 0.55;95%CI:0.31-0.98, respectively). CONCLUSIONS: Daily step counts and PF levels were negatively associated with having one or more MRF among Azorean adolescents. Our findings emphasize the importance of promoting and increasing regular PA and PF to reduce the public health burden of chronic diseases associated with a sedentary lifestyle.


Assuntos
Exercício Físico , Síndrome Metabólica/epidemiologia , Atividade Motora , Aptidão Física , Adolescente , Estudos Transversais , Feminino , Humanos , Masculino , Portugal/epidemiologia , Fatores de Risco
14.
Metab Syndr Relat Disord ; 8(5): 443-9, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20854056

RESUMO

BACKGROUND: Metabolic syndrome, a predecessor of cardiovascular disease and type 2 diabetes, has become prevalent in adolescents. This study aimed to estimate the prevalence of metabolic syndrome and its components and to analyze the relationship between metabolic syndrome and overall physical fitness levels in a sample of Azorean adolescents. METHODS: A cross-sectional school-based study, the Azorean Physical Activity and Health Study II, was conducted on 517 adolescents (297 girls, 220 boys) aged 15-18 years old from the Azorean Islands. Body height, weight, waist circumference, and arterial blood pressure were measured according to standards. Fasting intravenous blood samples were analyzed (high-density lipoprotein cholesterol, triglycerides, and glucose). Physical fitness was assessed using five tests from Fitnessgram Test Battery 8.0: Curl-up, push-up, trunk lift, pacer, and sit-and-reach. Adolescents were then classified as being in the healthy zone or above or under the healthy zone. Metabolic syndrome was defined according to the 2007 International Diabetes Federation's guidelines for adolescents. RESULTS: The prevalence of metabolic syndrome was 5% (4.7% in girls and 5.5% in boys, P > 0.05). Waist circumference was the most prevalent component (32.9%), and hypertriglyceridemia the least (4.4%). Logistic regression analysis showed that after adjusting for pubertal stage and socioeconomic status, unfit adolescents (healthy zone criteria in

Assuntos
Síndrome Metabólica/diagnóstico , Aptidão Física , Adolescente , Açores , Estudos Transversais , Feminino , Humanos , Hipertrigliceridemia/complicações , Masculino , Síndrome Metabólica/etnologia , Razão de Chances , Prevalência , Fatores de Risco , Classe Social , Circunferência da Cintura
15.
J Nanosci Nanotechnol ; 10(4): 2779-86, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20355501

RESUMO

Photoluminescent materials were prepared by introducing lanthanide complexes of 4'-formylbenzo-15-crown-5 (C15H20O6) into a silica matrix obtained by the sol-gel method. The new lanthanide complexes [Ln(C15H20O6)(NO3)3(H2O)2] (Ln3+ = Sm3+, Eu3+ and Tb3+) were synthesized and were fully characterised using spectroscopic techniques, and elemental and thermogravimetric analysis. Photoluminescence measurements were performed for the isolated Eu3+ and Tb3+ complexes as well as for their related silica based materials. A detailed comparative analysis on the photoluminescent properties of the EU3+ complex and of its derived silica material was carried out.

16.
Inorg Chem ; 49(7): 3428-40, 2010 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-20225832

RESUMO

The hydrothermal reaction between lanthanide nitrates and 2,3-pyrazinedicarboxylic acid led to a new series of two-dimensional (2D) lanthanide-organic frameworks: [Ln(2)(2,3-pzdc)(2)(ox)(H(2)O)(2)](n) [where 2,3-pzdc(2-) = 2,3-pyrazinedicarboxylate, ox(2-) = oxalate, and Ln(III) = Ce, Nd, Sm, Eu, Gd, Tb, or Er]. The structural details of these materials were determined by single-crystal X-ray diffraction (for Ce(3+) and Nd(3+)) that revealed the formation of a layered structure. Cationic monolayers of {(infinity)(2)[Ln(2,3-pzdc)(H(2)O)](+)} are interconnected via the ox(2-) ligand leading to the formation of neutral (infinity)(2)[Ln(2)(2,3-pzdc)(2)(ox)(H(2)O)(2)] bilayer networks; structural cohesion of the crystalline packing is reinforced by the presence of highly directional O-H...O hydrogen bonds between adjacent bilayers. Under the employed hydrothermal conditions 2,3-pyrazinedicarboxylic acid can be decomposed into ox(2-) and 2-pyrazinecarboxylate (2-pzc(-)), as unequivocally proved by the isolation of the discrete complex [Tb(2)(2-pzc)(4)(ox)(H(2)O)(6)].10H(2)O. Single-crystal X-ray diffraction of this latter complex revealed its co-crystallization with an unprecedented (H(2)O)(16) water cluster. Photoluminescence measurements were performed for the Nd(3+), Sm(3+), Eu(3+), and Tb(3+) compounds which show, under UV excitation at room temperature, the Ln(3+) characteristic intra-4f(N) emission peaks. The energy level of the triplet states of 2,3-pyrazinedicarboxylic acid (18939 cm(-1)) and oxalic acid (24570 cm(-1)) was determined from the 12 K emission spectrum of the Gd(3+) compound. The (5)D(0) and (5)D(4) lifetime values (0.333 +/- 0.006 and 0.577 +/- 0.017 ms) and the absolute emission quantum yields (0.13 +/- 0.01 and 0.05 +/- 0.01) were determined for the Eu(3+) and Tb(3+) compounds, respectively. For the Eu(3+) compound the energy transfer efficiency arising from the ligands' excited states was estimated (0.93 +/- 0.01).

17.
Acta Crystallogr Sect E Struct Rep Online ; 64(Pt 4): m529-30, 2008 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-21201993

RESUMO

In the title compound, [KTb(C(6)H(4)NO(2))(4)(H(2)O)]·2.5H(2)O, each Tb(3+) centre is coordinated by four N and five O atoms from five distinct picolinate ligands in a geometry resembling a highly distorted tricapped trigonal prism. One of the ligands establishes a skew bridge between neighbouring Tb(3+) centres, leading to the formation of one-dimensional anionic polymeric chains, {[(C(6)H(4)NO(2))(4)Tb](-)}(n), running along the direction [010]. Each K(+) cation is seven-coordinated by six O atoms from one anionic polymeric chain and one water mol-ecule [K⋯O 2.676 (3)-3.208 (4) Å]. The uncoordinated water mol-ecules are involved in O-H⋯O hydrogen bonding.

18.
Nanotechnology ; 19(15): 155601, 2008 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-21825615

RESUMO

We describe, in this paper, the sol-gel synthesis of di-ureasil based nanocomposites prepared in situ in the presence of organically capped CdSe quantum dots (QDs) or CdSe QDs which have been coated with a ZnS shell. For the latter a new chemical route to coat the CdSe QDs with ZnS shells was investigated and is now reported. The QDs became well dispersed in the final nanocomposites, whose microstructural homogeneity was evaluated by atomic force microscopy (AFM) and transmission electron microscopy (TEM) analyses. In order to understand the optical behaviour of di-ureasil containing QDs, a detailed photoluminescent study was undertaken for a selected particle size distribution of ZnS coated CdSe QDs (d∼4.5 nm). Emission quantum yields up to 0.11 were measured in the final nanocomposites that present a huge (between 3 and 6 orders of magnitude) increase in the lifetime of the QDs (relative to that of isolated ones), as a result of energy transfer occurring between the intimately mixed di-ureasil host and the QDs.

19.
Artigo em Inglês | MEDLINE | ID: mdl-15951212

RESUMO

Glial fibrillary acidic protein (GFAP) is the major component of intermediate glial filaments in the central nervous system of many vertebrates and invertebrates. In vertebrates, this protein is mainly expressed in mature astrocytes and provides structural cell stability. The highly conserved structure and glial specificity of this protein have allowed studies of ontogeny and phylogeny using antibodies. The present study investigated the ontogenetic profile and molecular weight of GFAP in the snail, Megalobulimus abbreviatus, particularly in cerebral ganglia and subesophageal mass, by immunohistochemistry and immunoblotting. Our results confirm and extend previous studies about glial intermediate filaments in snails, showing: (i) a higher GFAP content in cerebral ganglia than in subesophageal mass; (ii) a developmental increase of GFAP immunocontent in cerebral ganglia, as described in Vertebrates; and (iii) an electrophoretic band for GFAP of approximately 55 kDa.


Assuntos
Gânglios dos Invertebrados/química , Proteína Glial Fibrilar Ácida/análise , Caramujos/química , Animais , Imuno-Histoquímica , Masculino , Peso Molecular , Ratos , Ratos Wistar , Caramujos/crescimento & desenvolvimento , Distribuição Tecidual
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