Investigation of photorefractive subharmonics in the absence of wavemixing

Using a new optical configuration free from the influence of photorefractive optical nonlinearity, we investigate the main characteristics of the spatial subharmonic K/2 excited in a Bi12SiO20 crystal by a light-intensity pattern with wave vector K and frequency O. It is shown that in a large region of intensity and applied electric field the optimum value O of the frequency corresponds to the conditions of parametric excitation of the weakly damped eigenmodes of the medium: the space-charge waves. The threshold and above-threshold characteristics of the subharmonic regime are in good agreement with the theory.

Picosecond soliton transmission using concatenated nonlinear optical loop-mirror intensity filters

The issues involved in employing nonlinear optical loop mirrors (NOLMs) as intensity filters in picosecond soliton transmission were examined in detail. It was shown that inserting NOLMs into a periodically amplified transmission line allowed picosecond solitons to be transmitted under conditions considered infeasible until now. The loop mirrors gave dual function, removing low-power background dispersive waves through saturable absorption and applying a negative feedback mechanism to control the amplitude of the solitons. The stochastic characteristics of the pulses that were due to amplifier spontaneous-emission noise were investigated, and a number of new properties were determined. In addition, the mutual interaction between pulses was also significantly different from that observed for longer-duration solitons. The impact of Raman scattering in the computations was included and it was shown that soliton self-frequency shifts may be eliminated by appropriate bandwidth restrictions.

Trajetórias e fatores associados a qualidade de vida de mães de recém-nascidos pré-termos de muito baixo peso até três anos após o parto

Preterm birth is a public health problem worldwide. It holds growing global incidence rates, high mortality rates and a risk of the long-term sequelae in the newborn. It is also poses burden on the family and society. Mothers of very low birth weight (VLBW) preterm infants may develop psychological disorders, and impaired quality of life (QoL). Factors related to mothers and children in the postpartum period may be negatively associated with the QoL of these mothers. The aim of this study was to assess factors possibly associated with the QoL of mothers of VLBW preterm newborns during the first three years after birth. Mothers of VLBW preterm answered the World Health Organization Quality of Life (WHOQOL)-bref and the Beck Depression Inventory (BDI) in five time points up to 36 months postpartum, totalizing 260 observations. The WHOQOL–bref scores were compared and correlated with sociodemographic and clinical variables of mothers and children at discharge (T0) and at six (T1), twelve (T2), 24 (T3) and 36 (T4) months after the delivery. We used the Kruskal Wallis test to compared scores across different time points and correlated WHOQOL-bref scores with the sociodemographic and clinical variables of mothers and preterm infants. Multiple linear regression models were used to evaluate the contribution of these variables for the QoL of mothers. The WHOQOL–bref scores at T1 and T2 were higher when compared to scores in T0 in the physical health dimension (p = 0.013). BDI scores were also higher at T1 and T2 than those at T0 (p = 0.027). Among the maternal variables that contributed most to the QoL of mothers, there were: at T0, stable marital union (b= 13.60; p= 0.000) on the social relationships dimension, gestational age (b= 2.38; p= 0.010) in the physical health dimension; post-hemorrhagic hydrocephalus (b= -10.05; p= 0.010; b= -12.18; p= 0.013, respectively) in the psychological dimension; at T1 and T2, Bronchopulmonary dysplasia (b= -7.41; p= 0.005) and female sex (b= 8,094; p= 0.011) in the physical health dimension and environment, respectively. At T3, family income (b= -12.75’ p= 0.001) in the environment dimension, the SNAPPE neonatal severity score (b= -0.23; p= 0.027) on the social relationships dimension; at the T4, evangelical religion (b= 8.11; p= 0.019) and post-hemorrhagic hydrocephalus (b: -18.84 p: 0.001) on the social relationships dimension. The BDI scores were negatively associated with WHOQOL scores in all dimensions and at all times points: (-1.42 ≤ b ≤ -0.36; T0, T1, T2, T3 and T4). We conclude that mothers of preterm infants VLBW tend to have a transient improvement in the physical well-being during the first postpartum year. Their quality of life seems to return to levels at discharge between two and three years after delivery. The presence of maternal depressive symptoms and diagnosis of post-hemorrhagic hydrocephalus or BDP are factors negatively associated with the QoL of mothers. Social, religious and economic variables are positively associated with the QoL of mothers of VLBW preterm.

De Invloed van Altruïsme op de Samenhang tussen Leeftijd en Mentale Veerkracht

Het primaire doel van deze studie was meer helderheid te krijgen over de invloed van altruïsme op de positieve associatie tussen leeftijd en mentale veerkracht. Het secundaire doel was een factor te kunnen aanwijzen die de positieve relatie tussen leeftijd en mentale veerkracht zou mediëren of anderszins verklaren. Meer begrip over factoren die samenhangen met mentale veerkracht, zou kunnen leiden tot de ontwikkeling en verfijning van trainingen ter bevordering van mentale veerkracht. De studie kende een cross-sectionele opzet met één meetmoment. Van de 92 oudere deelnemers werden er 66 met hulp van sleuteldeelnemers in het netwerk van de onderzoeker gevonden. De overige 26 zijn oudere deelnemers uit de database van de OU. Alle jongvolwassenen zijn afkomstig uit de database van de OU. In totaal zijn er 160 deelnemers geïncludeerd in deze studie, waarvan 68 jongvolwassenen tussen de 18 en 45 en 92 oudere volwassenen van 60 jaar of ouder. De uitgevoerde regressie analyses waren gericht op de veronderstelde mediërende verklaring door altruïsme van de relatie tussen leeftijd en mentale veerkracht. Mentale veerkracht werd gemeten met de Resilience Scale (RS-nl; Portzky, 2010). De Nederlandse vertaling van de NEO Five Factor Inventory (NEO-FFI; Hoekstra, Ormel & Fruyt, 1996) werd gebruikt om altruïsme te meten. Van de RS-nl is de totaalscore geanalyseerd, van de NEO zijn alleen de vragen met betrekking tot altruïsme geanalyseerd. De mediatie-analyse is uitgevoerd middels de 4 stappen methode van Baron en Kenny (beschreven in Verboon, 2010). De hypothese betreffende de positieve samenhang tussen leeftijd en mentale veerkracht werd bevestigd (b = .12, t(153) = 3.91, p < .001). Er werd geen samenhang tussen leeftijd en altruïsme of tussen altruïsme en mentale veerkracht gevonden. Hierdoor kon er geen sprake zijn van mediatie door altruïsme op de relatie tussen leeftijd en mentale veerkracht.

La supplémentation nutritionnelle dans la prévention et le traitement des troubles cognitifs associés à la maladie d’Alzheimer

Cette recension systématique analyse 19 essais cliniques randomisés contre placebo qui mesurent l’effet de suppléments d’oméga-3, de vitamines B (B6, B9 et B12), ou de vitamines antioxydantes (C et E), sur le fonctionnement cognitif d’aînés avec ou sans trouble cognitif. Les bases de données consultées pour la recherche des articles sont Cochrane Library, Current Contents, EBSCO, EMBASE, MEDLINE et PsycNet. Les mots clés utilisés sont «alzheimer’s disease», or «mild cognitive impairment», or «cognitive decline»; and «dietary supplements» or «vitamin C», or «vitamin E», or «alpha-tocopherol», or «vitamin B», or «cobalamin», or «folic acid», or «omega 3», or «fatty acids»; and «prevention», or «treatment». La recherche inclut les articles publiés en anglais et en français, de 1999 à juin 2014. Les différents suppléments à l’étude sont bien tolérés et sécuritaires. Des résultats significatifs sont enregistrés sur des mesures cognitives suite à la supplémentation en oméga-3, et en vitamines B, chez des participants sans trouble cognitif ou avec un diagnostic de trouble cognitif léger. Chez les participants atteints de la maladie d’Alzheimer, des résultats significatifs sont surtout enregistrés sur des mesures fonctionnelles, de symptômes psychologiques et comportementaux, ou de qualité de vie, suite à l’administration d’un supplément nutritionnel. La présence d’une hétérogénéité importante dans la méthodologie des essais cliniques limite toutefois les conclusions quant à la pertinence clinique de ces traitements. L’établissement de lignes directrices suite à un consensus d’experts s’avère nécessaire afin d’uniformiser la recherche sur cette nouvelle piste d’intervention dans la prévention et le traitement de la maladie d’Alzheimer.

Influência da tecnologia no desenvolvimento do pensamento algébrico : um estudo no 1º CEB

Relatório de Estágio apresentado à Escola Superior de Educação do Instituto Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Educação Pré-Escolar e Ensino do 1º Ciclo do Ensino Básico.

Estudo comparativo entre eletrodo fixo e eletrodo móvel (caneta) no fortalecimento perineal

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Ciências Médicas, Programa de Pós-Graduação em Ciências Médicas, 2011.

Deflazacort Versus Prednisolone: Randomized Controlled Trial in Treatment of Children With Idiopathic Nephrotic Syndrome

Background: Corticosteroids are the main therapy of nephrotic syndrome and goal of corticosteroid therapy is to obtain maximum clinical benefit with minimum adverse effects. Children are more vulnerable to side effects of corticosteroids related to growth and adrenal suppression, so a search for an alternative steroid with fewer side-effects is underway. Deflazacort is an oxazoline derivative and preliminary data suggest reduced osteoporosis, lesser growth retardation and weight gain with deflazacort. Objectives: This study was done to compare the effectiveness and safety of deflazacort in idiopathic nephrotic syndrome. Patients and Methods: Twenty five children with age between 2 to 12 years, with idiopathic nephrotic syndrome were enrolled. They were randomly assigned to receive deflazacort (Group A, n = 12) or prednisolone (Group B, n = 13) and were followed up for six months. Results: All children of group A and 11 of group B had remission. Two children from group B were steroid resistant. Mean time taken to induce remission was significantly (P = 0.012) less in group A (10.25 ± 2.41 days) than group B (12.55 ± 1.44 days). One patient in group A had relapse on follow up as compared to 3 in group B (P = 0.58). Statistically significant difference (P = 0.03) in change in mean height was found between group A (2.13 ± 0.50cm) and B (1.44 ± 0.45 cm), with group B gaining less height. Conclusions: Remission rate in both groups was comparable although time taken to induce remission was shorter in deflazacort group and there was a significant difference in change of mean height on follow up with prednisolone group gaining lesser height.

A narrow-band ultraviolet B course improves vitamin D balance and alters cutaneous CYP27A1 and CYP27B1 mRNA expression levels in haemodialysis patients supplemented with oral vitamin D

Background: Chronic kidney disease (CKD) patients on dialysis are prone to vitamin D insufficiency despite oral vitamin D supplementation. Here, we studied whether narrow-band ultraviolet B (NB-UVB) exposures improve vitamin D balance.<br/><br/>Methods: 14 haemodialysis patients and 15 healthy subjects receiving oral cholecalciferol 20 µg daily got nine NB-UVB exposures on the entire body. Serum 25-hydroxyvitamin D (25(OH)D) was measured by radioimmunoassay. Cutaneous mRNA expression levels of CYP27A1 and CYP27B1, two enzymes required for hydroxylation of vitamin D into its active metabolite, were also measured. <br/><br/>Results: The baseline serum 25(OH)D concentration was 57.6 ± 18.2 nmol/l in the CKD patients and 74.3 ± 14.8 nmol/l in the healthy subjects. The NB-UVB course increased serum 25(OH)D by 14.0 nmol/l (95% CI 8.7-19.5) and 17.0 nmol/l (CI 13.7-20.2), respectively. At baseline the CKD patients showed significantly increased CYP27B1 levels compared to the healthy subjects. <br/><br/>Conclusions: A short NB-UVB course is an efficient way to improve vitamin D balance in CKD patients on dialysis who are receiving oral vitamin D supplementation. The increased cutaneous CYP27B1 levels in the CKD patients suggest that the loss of renal activity of this enzyme is at least partially compensated for by the skin.<br/>

Narrow-band ultraviolet B treatment boosts serum 25-hydroxyvitamin D in patients with psoriasis on oral vitamin D supplementation

A course of treatment with narrow-band ultraviolet B (NB-UVB) improves psoriasis and increases serum 25-hydroxyvitamin D (25(OH)D). In this study 12 patients with psoriasis who were supplemented with oral cholecalciferol, 20 µg daily, were given a course of NB-UVB and their response measured. At baseline, serum 25(OH)D was 74.14 ± 22.9 nmol/l. At the 9th exposure to NB-UVB 25(OH)D had increased by 13.2 nmol/l (95% confidence interval (95% CI) 7.2–18.4) and at the 18th exposure by 49.4 nmol/l (95% CI 35.9–64.6) above baseline. Psoriasis Area Severity Index score improved from 8.7 ± 3.5 to 4.5 ± 2.0 (p < 0.001). At baseline, psoriasis lesions showed low vitamin D metabolizing enzyme (CYP27A1, CYP27B1) and high human β-defensin-2 mRNA expression levels compared with those of the healthy subjects. In conclusion, NB-UVB treatment significantly increases serum 25(OH)D in patients with psoriasis who are taking oral vitamin D supplementation, and the concentrations remain far from the toxicity level. Healing psoriasis lesions show similar mRNA expression of vitamin D metabolizing enzymes, but higher antimicrobial peptide levels than NB-UVB-treated skin in healthy subjects.

Solar ultraviolet-B radiation and vitamin D: a cross-sectional population-based study using data from the 2007 to 2009 Canadian Health Measures Survey

Background: Exposure to solar ultraviolet-B (UV-B) radiation is a major source of vitamin D3. Chemistry climate models project decreases in ground-level solar erythemal UV over the current century. It is unclear what impact this will have on vitamin D status at the population level. The purpose of this study was to measure the association between ground-level solar UV-B and serum concentrations of 25-hydroxyvitamin D (25(OH)D) using a secondary analysis of the 2007 to 2009 Canadian Health Measures Survey (CHMS). Methods: Blood samples collected from individuals aged 12 to 79 years sampled across Canada were analyzed for 25(OH)D (n=4,398). Solar UV-B irradiance was calculated for the 15 CHMS collection sites using the Tropospheric Ultraviolet and Visible Radiation Model. Multivariable linear regression was used to evaluate the association between 25(OH)D and solar UV-B adjusted for other predictors and to explore effect modification. Results: Cumulative solar UV-B irradiance averaged over 91 days (91-day UV-B) prior to blood draw correlated significantly with 25(OH)D. Independent of other predictors, a 1 kJ/m 2 increase in 91-day UV-B was associated with a significant 0.5 nmol/L (95% CI 0.3-0.8) increase in mean 25(OH)D (P =0.0001). The relationship was stronger among younger individuals and those spending more time outdoors. Based on current projections of decreases in ground-level solar UV-B, we predict less than a 1 nmol/L decrease in mean 25(OH)D for the population. Conclusions: In Canada, cumulative exposure to ambient solar UV-B has a small but significant association with 25(OH)D concentrations. Public health messages to improve vitamin D status should target safe sun exposure with sunscreen use, and also enhanced dietary and supplemental intake and maintenance of a healthy body weight.

Does a high UV environment ensure adequate vitamin D status?

This study assesses the Vitamin D status of 126 healthy free-living adults aged 18–87 years, in southeast Queensland, Australia (27°S) at the end of the 2006 winter. Participants provided blood samples for analysis of 25(OH)D (the measure of an individual’s Vitamin D status), PTH, Calcium, Phosphate, and Albumin, completed a questionnaire on sun-protective/sun-exposure behaviours, and were assessed for phenotypic characteristics such as skin/hair/eye colour and BMI. We found that 10.2% of the participants had serum 25(OH)D levels below 25 nmol/l (considered deficient) and a further 32.3% had levels between 25 nmol/l and 50 nmol/l (considered insufficient). Our results show that low levels of 25(OH)D can occur in a substantial proportion of the population at the end of winter, even in a sunny climate. 25(OH)D levels were higher amongst those who spent more time in the sun and lower among obese participants (BMI > 30) than those who were not obese (BMI < 30). 25(OH)D levels were also lower in participants who had black hair, dark/olive skin, or brown eyes, when compared with participants who had brown or fair hair, fair skin, or blue/green eyes. No associations were found between 25(OH)D status and age, gender, smoking status, or the use of sunscreen.

Recruitment and results of a pilot trial of vitamin D supplementation in the general population of Australia

Context: The benefits of high serum levels of 25-hydroxyvitamin D [25(OH)D] are unclear. Trials are needed to establish an appropriate evidence base. Objective: We plan to conduct a large-scale trial of vitamin D supplementation for the reduction of cancer incidence and overall mortality and report here the methods and results of a pilot trial established to inform its design. Design: Pilot D-Health was a randomized trial carried out in a general community setting with 12 months intervention and follow-up. Participants: Participants were 60- to 84-yr-old residents of one of the four eastern Australian states who did not have any vitamin D-related disorders and who were not taking more than 400 IU supplementary vitamin D per day. A total of 644 participants were randomized, and 615 completed the study (two persons withdrew because of nonserious adverse events). Interventions: The interventions were monthly doses of placebo or 30,000 or 60,000 IU vitamin D3. Main Outcomes: The main outcomes were the recruitment rate and changes in serum 25(OH)D. Results: Ten percent of those approached were recruited. At baseline, the mean 25(OH)D was 42 nmol/liter in all three study arms. The mean change in 25(OH)D in the placebo group was 0.12 nmol/liter, compared with changes of 22 and 36 nmol/liter in the 30,000- and 60,000-IU groups, respectively. Conclusions: The D-Health pilot has shown that a large trial is feasible in Australia and that a dose of 2000 IU/d will be needed to ensure that a large proportion of the population reaches the target serum 25(OH)D level. Copyright © 2012 by The Endocrine Society.