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Financial capacity (FC) is conceptualized as a dimension that encompasses a wide range of basic aptitudes and the capacity to judge and assess situations and make decisions according to one best interests. The Numerical Activities of Daily-Living-Financial (NADL-F) is an instrument of FC for clinical use developed in Italy. This study aims to perform a preliminary analysis on the psychometric characteristics of the Portuguese version of NADL-F. NADL-F as well as other neuropsychological instruments were administered to three groups: Healthy Control (n = 11); Mild Neurocognitive Disorder group (n = 19); Major Neurocognitive Disorder group (n = 19). NADL-F and its tasks were considered acceptable, showed good reliability for the entire sample (α = .808) and the majority of the domains correlated significantly with each other and with the total scale. Between group comparisons showed significant differences regarding all domains. Arithmetic, schooling and executive functioning accounted for 54.1% of the variance on the test. The Portuguese version of NADL-F proved to be an acceptable and valid instrument of assessing FC in the context of cognitive aging. NADL-F is an instrument that emulates real life financial situations, and it can be used in a second level of evidence in the clinical model of FC assessment.
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Envelhecimento Cognitivo , Atividades Cotidianas/psicologia , Envelhecimento , Humanos , Testes Neuropsicológicos , Portugal , Psicometria , Reprodutibilidade dos TestesRESUMO
BACKGROUND: A subset of patients with phenylketonuria benefit from treatment with tetrahydrobiopterin (BH4), although there is no consensus on the definition of BH4 responsiveness. The aim of this study therefore was to gain insight into the definitions of long-term BH4 responsiveness being used around the world. METHODS: We performed a web-based survey targeting healthcare professionals involved in the treatment of PKU patients. Data were analysed according to geographical region (Europe, USA/Canada, other). RESULTS: We analysed 166 responses. Long-term BH4 responsiveness was commonly defined using natural protein tolerance (95.6%), improvement of metabolic control (73.5%) and increase in quality of life (48.2%). When a specific value for a reduction in phenylalanine concentrations was reported (n = 89), 30% and 20% were most frequently used as cut-off values (76% and 19% of respondents, respectively). When a specific relative increase in natural protein tolerance was used to define long-term BH4 responsiveness (n = 71), respondents most commonly reported cut-off values of 30% and 100% (28% of respondents in both cases). Respondents from USA/Canada (n = 50) generally used less strict cut-off values compared to Europe (n = 96). Furthermore, respondents working within the same center answered differently. CONCLUSION: The results of this study suggest a very heterogeneous situation on the topic of defining long-term BH4 responsiveness, not only at a worldwide level but also within centers. Developing a strong evidence- and consensus-based definition would improve the quality of BH4 treatment.
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Biopterinas/análogos & derivados , Fenilalanina/genética , Fenilcetonúrias/tratamento farmacológico , Biopterinas/efeitos adversos , Biopterinas/uso terapêutico , Canadá/epidemiologia , Europa (Continente)/epidemiologia , Humanos , Fenilalanina/sangue , Fenilalanina Hidroxilase/genética , Fenilcetonúrias/sangue , Fenilcetonúrias/epidemiologia , Fenilcetonúrias/patologia , Estados Unidos/epidemiologiaRESUMO
Light scattering by disordered media is a ubiquitous effect. After passing through them, the light acquires a random phase, masking or destroying associated information. Filtering this random phase is of paramount importance to many applications, such as sensing, imaging, and optical communication, to cite a few, and it is commonly achieved through computationally extensive post-processing using statistical correlation. In this work, we show that mixing noisy optical modes of various complexity in a second-order nonlinear medium can be used for efficient and straightforward filtering of a random wavefront under sum-frequency generation processes without utilizing correlation-based calculations.
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This study aimed to evaluate the psychosocial differences between patients with psoriasis in different phases of the disease. Seventy-one patients in exacerbation and 83 in remission were evaluated regarding sociodemographic, clinical and psychological variables, on the premise that the visibility of lesions (exacerbation phase) may impact the emotional regulation and embitterment. A regression analysis was performed to identify the variables that contribute to explain embitterment: a diagnosis of anxiety and/or depression and psoriasis severity are the identified ones. The results point to higher values of emotional dysregulation and embitterment, as well as more critical clinical variables in patients with active disease, namely, alcohol and coffee consumption, smoking and less satisfaction with current treatment, more diagnoses and more family history of anxiety and depression, more psychology/psychiatry consultations and more use of anxiolytics and antidepressants. However, only the results referring to alcohol consumption and embitterment are significantly higher in subjects in the exacerbation phase of the disease. Particular clinical attention should be provided to patients in exacerbation phase regarding psychotherapeutic approach.
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Regulação Emocional/fisiologia , Psoríase/psicologia , Índice de Gravidade de Doença , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psoríase/terapia , Inquéritos e QuestionáriosRESUMO
By considering parity-defined Laguerre-Gaussian (LG) and Hermite-Gaussian (HG) beams as input modes, we present arguments through experimental and theoretical results in order to affirm that using HG modes as bases is more suitable for optical mode conversion than using LG modes. By analyzing the normalized overlap integral and the generated modes, we determine a clear rule for the dominant mode for nonlinear mixing of HG beams, while the same is not possible for LG beams. In addition, examples of optical modal conversion using both HG and LG modes as input beams are demonstrated.
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INTRODUCTION: The few published case reports of co-existent disease with phenylketonuria (PKU) are mainly genetic and familial conditions from consanguineous marriages. The clinical and demographic features of 30 subjects with PKU and co-existent conditions were described in this multi-centre, retrospective cohort study. METHODS: Diagnostic age of PKU and co-existent condition, treatment regimen, and impact of co-existent condition on blood phenylalanine (Phe) control and PKU management were reported. RESULTS: 30 patients (11 males and 19 females), with PKU and a co-existent condition, current median age of 14 years (range 0.4 to 40 years) from 13 treatment centres from Europe and Turkey were described. There were 21 co-existent conditions with PKU; 9 were autoimmune; 6 gastrointestinal, 3 chromosomal abnormalities, and 3 inherited conditions. There were only 5 cases of parental consanguinity. Some patients required conflicting diet therapy (n=5), nutritional support (n=7) and 5 children had feeding problems. There was delayed diagnosis of co-existent conditions (n=3); delayed treatment of PKU (n=1) and amenorrhea associated with Grave's disease that masked a PKU pregnancy for 12 weeks. Co-existent conditions adversely affected blood Phe control in 47% (n=14) of patients. Some co-existent conditions increased the complexity of disease management and increased management burden for patients and caregivers. CONCLUSIONS: Occurrence of co-existent disease is not uncommon in patients with PKU and so investigation for co-existent disorders when the clinical history is not completely consistent with PKU is essential. Integrating care of a second condition with PKU management is challenging.
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Doenças Autoimunes/terapia , Aberrações Cromossômicas , Gerenciamento Clínico , Gastroenteropatias/terapia , Fenilalanina/sangue , Fenilcetonúrias/terapia , Adolescente , Adulto , Doenças Autoimunes/sangue , Doenças Autoimunes/complicações , Doenças Autoimunes/diagnóstico , Biopterinas/análogos & derivados , Biopterinas/uso terapêutico , Criança , Pré-Escolar , Consanguinidade , Dieta , Europa (Continente) , Feminino , Gastroenteropatias/sangue , Gastroenteropatias/complicações , Gastroenteropatias/diagnóstico , Humanos , Lactente , Masculino , Fenilcetonúrias/sangue , Fenilcetonúrias/complicações , Fenilcetonúrias/diagnóstico , Gravidez , Estudos Retrospectivos , TurquiaRESUMO
BACKGROUND: Three international surveys were developed aiming to identify the current nutrition educational tools used in the management of phenylketonuria (PKU) and the perceived effectiveness of these tools by clinicians, parents and patients. METHODS: The first two surveys were distributed through the Metabolic Dietitians ListServe (pno-metabl@listserv.cc.emory.edu), and the third survey was distributed by international clinics and the National PKU Alliance website (www.npkua.org). A total of 888 responses (S1, n = 88; S2, n = 81; S3, n = 719) were collected from all three surveys. The surveys represent participants from 17 countries, in Europe; North America (USA and Canada); Mexico; Argentina; Turkey; Australia; and Africa (Tunisia). RESULTS: A consistent decline in 'parents as role models' as an educational tool was observed starting at age 10 years. Patients responded they feel their families are the most effective form of education, whereas handouts were selected as the least effective educational tool by patients. Parents responded they feel the most effective educational tool is one-on-one counselling. Patients and parents show a desirable trend in wanting to attend group clinic, even in centres where this type of educational tool is not offered. CONCLUSIONS: There was a discrepancy between clinicians and patient views regarding the perceived effectiveness of the nutrition education tools. Future research is needed surrounding the impact nutrition education may have on improved dietary compliance in patients with PKU.
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Gerenciamento Clínico , Educação em Saúde/métodos , Inquéritos Epidemiológicos , Terapia Nutricional/métodos , Fenilcetonúrias/dietoterapia , Adolescente , Adulto , Criança , Aconselhamento/educação , Dieta , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Pais/educação , Cooperação do Paciente , Médicos , Projetos Piloto , Adulto JovemRESUMO
Patients with phenylketonuria (PKU) encompass an 'at risk' group for micronutrient imbalances. Optimal nutrient status is challenging particularly when a substantial proportion of nutrient intake is from non-natural sources. In PKU patients following dietary treatment, supplementation with micronutrients is a necessity and vitamins and minerals should either be added to supplement phenylalanine-free l-amino acids or given separately. In this literature review of papers published since 1990, the prevalence of vitamin and mineral deficiency is described, with reference to age of treatment commencement, type of treatment, dietary compliance, and dietary practices. Biological micronutrient inadequacies have been mainly reported for zinc, selenium, iron, vitamin B12 and folate. The aetiology of these results and possible clinical and biological implications are discussed. In PKU there is not a simple relationship between the dietary intake and nutritional status, and there are many independent and interrelated complex factors that should be considered other than quantitative nutritional intake.
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Suplementos Nutricionais , Micronutrientes/deficiência , Minerais/administração & dosagem , Estado Nutricional , Fenilcetonúrias/fisiopatologia , Deficiência de Vitamina B 6/etiologia , Vitaminas/administração & dosagem , Adolescente , Adulto , Envelhecimento , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Micronutrientes/administração & dosagem , Necessidades Nutricionais , Cooperação do Paciente , Fenilcetonúrias/complicações , Fenilcetonúrias/dietoterapia , Adulto JovemRESUMO
For almost all patients with PKU, a low phenylalanine diet is the basis of the treatment despite a widely varying natural protein tolerance. A vitamin and mineral supplement is essential and it is commonly added to a phenylalanine-free (phe-free) source of L-amino acids. In PKU, many phe-free L-amino acid supplements have age-specific vitamin and mineral profiles to meet individual requirements. The main micronutrient sources are chemically derived and their delivery dosage is usually advised in three or more doses throughout the day. Within the EU, the composition of VM (vitamin and mineral) phe-free L-amino acid supplements is governed by the Foods for Special Medical Purposes (FSMP) directive (European Commission Directive number 1999/21/EC and amended by Directive 2006/141/EC). However the micronutrient composition of the majority fails to remain within FSMP micronutrient maximum limits per 100 kcal due to their low energy content and so compositional exceptions to the FSMP directive have to be granted for each supplement. All patients with PKU require an annual nutritional follow-up, until it has been proven that they are not at risk of any vitamin and mineral imbalances. When non-dietary treatments are used to either replace or act as an adjunct to diet therapy, the quality of micronutrient intake should still be considered important and monitored systematically. European guidelines are required about which micronutrients should be measured and the conditions (fasting status) for monitoring.
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Micronutrientes/administração & dosagem , Minerais/administração & dosagem , Fenilcetonúrias/dietoterapia , Vitaminas/administração & dosagem , Suplementos Nutricionais , União Europeia , Humanos , Micronutrientes/efeitos adversos , Minerais/efeitos adversos , Fenilalanina/deficiência , Fenilalanina/metabolismo , Vitaminas/efeitos adversosRESUMO
Sapropterin treatment, with or without dietary treatment, improves blood phenylalanine control, increases phenylalanine tolerance, and may reduce the day-to-day dietary treatment burden in a subset of patients with phenylketonuria (PKU). Balancing the need for maintained control of blood phenylalanine with diet relaxation is complex when administering sapropterin. We present a series of seven patient cases with PKU that illustrate important aspects of using sapropterin with diet in the management of the disorder.
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Biopterinas/análogos & derivados , Fenilcetonúrias/tratamento farmacológico , Adolescente , Biopterinas/administração & dosagem , Biopterinas/uso terapêutico , Criança , Pré-Escolar , Dieta com Restrição de Proteínas , Feminino , Humanos , Lactente , Masculino , Adesão à Medicação , Fenilalanina/sangue , Fenilcetonúrias/sangue , Fenilcetonúrias/dietoterapia , Qualidade de Vida , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Within Europe, the management of pyridoxine (B6) non-responsive homocystinuria (HCU) may vary but there is limited knowledge about treatment practice. AIM: A comparison of dietetic management practices of patients with B6 non-responsive HCU in European centres. METHODS: A cross-sectional audit by questionnaire was completed by 29 inherited metabolic disorder (IMD) centres: (14 UK, 5 Germany, 3 Netherlands, 2 Switzerland, 2 Portugal, 1 France, 1 Norway, 1 Belgium). RESULTS: 181 patients (73% >16 years of age) with HCU were identified. The majority (66%; n=119) were on dietary treatment (1-10 years, 90%; 11-16 years, 82%; and >16 years, 58%) with or without betaine and 34% (n=62) were on betaine alone. The median natural protein intake (g/day) on diet only was, by age: 1-10 years, 12 g; 11-16 years, 11 g; and >16 years, 45 g. With diet and betaine, median natural protein intake (g/day) by age was: 1-10 years, 13 g; 11-16 years, 20 g; and >16 years, 38 g. Fifty-two percent (n=15) of centres allocated natural protein by calculating methionine rather than a protein exchange system. A methionine-free l-amino acid supplement was prescribed for 86% of diet treated patients. Fifty-two percent of centres recommended cystine supplements for low plasma concentrations. Target treatment concentrations for homocystine/homocysteine (free/total) and frequency of biochemical monitoring varied. CONCLUSION: In B6 non-responsive HCU the prescription of dietary restriction by IMD centres declined with age, potentially associated with poor adherence in older patients. Inconsistencies in biochemical monitoring and treatment indicate the need for international consensus guidelines.
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Dieta com Restrição de Proteínas , Homocistinúria/dietoterapia , Piridoxina/metabolismo , Adolescente , Adulto , Betaína/administração & dosagem , Criança , Pré-Escolar , Europa (Continente) , Feminino , Homocisteína/sangue , Homocistinúria/sangue , Homocistinúria/epidemiologia , Homocistinúria/patologia , Humanos , Lactente , Masculino , Metionina/metabolismo , Inquéritos e Questionários , Resultado do TratamentoRESUMO
BACKGROUND: There is no published data comparing dietary management of urea cycle disorders (UCD) in different countries. METHODS: Cross-sectional data from 41 European Inherited Metabolic Disorder (IMD) centres (17 UK, 6 France, 5 Germany, 4 Belgium, 4 Portugal, 2 Netherlands, 1 Denmark, 1 Italy, 1 Sweden) was collected by questionnaire describing management of patients with UCD on prescribed protein restricted diets. RESULTS: Data for 464 patients: N-acetylglutamate synthase (NAGS) deficiency, n=10; carbamoyl phosphate synthetase (CPS1) deficiency, n=29; ornithine transcarbamoylase (OTC) deficiency, n=214; citrullinaemia, n=108; argininosuccinic aciduria (ASA), n=80; arginase deficiency, n=23 was reported. The majority of patients (70%; n=327) were aged 0-16y and 30% (n=137) >16y. Prescribed median protein intake/kg body weight decreased with age with little variation between disorders. The UK tended to give more total protein than other European countries particularly in infancy. Supplements of essential amino acids (EAA) were prescribed for 38% [n=174] of the patients overall, but were given more commonly in arginase deficiency (74%), CPS (48%) and citrullinaemia (46%). Patients in Germany (64%), Portugal (67%) and Sweden (100%) were the most frequent users of EAA. Only 18% [n=84] of patients were prescribed tube feeds, most commonly for CPS (41%); and 21% [n=97] were prescribed oral energy supplements. CONCLUSIONS: Dietary treatment for UCD varies significantly between different conditions, and between and within European IMD centres. Further studies examining the outcome of treatment compared with the type of dietary therapy and nutritional support received are required.
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Aminoácidos Essenciais/metabolismo , Dieta com Restrição de Proteínas , Distúrbios Congênitos do Ciclo da Ureia/dietoterapia , Distúrbios Congênitos do Ciclo da Ureia/patologia , Adolescente , Adulto , Aminoácido N-Acetiltransferase/deficiência , Arginase/metabolismo , Acidúria Argininossuccínica/dietoterapia , Carbono-Nitrogênio Ligases com Glutamina como Doadora de N-Amida/deficiência , Criança , Pré-Escolar , Citrulinemia/dietoterapia , Europa (Continente) , Humanos , Lactente , Recém-Nascido , Ornitina Carbamoiltransferase/metabolismo , Inquéritos e Questionários , Resultado do Tratamento , Distúrbios Congênitos do Ciclo da Ureia/enzimologiaRESUMO
Human Respiratory Syncytial Virus (hRSV) infection results in death and hospitalization of thousands of people worldwide each year. Unfortunately, there are no vaccines or specific treatments for hRSV infections. Screening hundreds or even thousands of promising molecules is a challenge for science. We integrated biological, structural, and physicochemical properties to train and to apply the concept of artificial intelligence (AI) able to predict flavonoids with potential anti-hRSV activity. During the training and simulation steps, the AI produced results with hit rates of more than 83%. The better AIs were able to predict active or inactive flavonoids against hRSV. In the future, in vitro and/or in vivo evaluations of these flavonoids may accelerate trials for new anti-RSV drugs, reduce hospitalizations, deaths, and morbidity caused by this infection worldwide, and be used as input in these networks to determine which parameter is more important for their decision.
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Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Humanos , Inteligência Artificial , Infecções por Vírus Respiratório Sincicial/diagnóstico , Infecções por Vírus Respiratório Sincicial/tratamento farmacológicoRESUMO
The same basic principles are used to deliver dietary treatment in PKU that was developed sixty years ago. Dietary treatment is undoubtedly very successful, but it has gradually evolved and been guided commonly by individual experience and expert opinion only. There is little international consensus about dietary practice with improvements in specialist dietary products concentrating on taste and presentation rather than nutritional composition. Many areas of dietary treatment have not been rigorously examined. In particular, the amino acid and micronutrient profile of Phenylalanine-free (phe-free) amino acids requires further study. In different formulations of phe-free amino acids, there are variations in the amino acid patterns as well the amount of essential and non essential amino acids per 100g/amino acids. The amount of added tyrosine and branch chain amino varies substantially, and in PKU specifically, there is little data about their relative absorption rates and bioavailability. In phe-free amino acids, there is evidence suggesting that some of the added micronutrients may be excessive and so the source and amount of each micronutrient should be scrutinized, with a need for the development of international nutritional composition standards exclusively for these products. There is a dearth of data about the life-long phenylalanine tolerance of patients or the nutritional state of adult patients treated with diet. There is a growing need to measure body composition routinely in children with PKU and with the rise in childhood obesity, it is important to measure body fatness and identify those who are at greatest risk of 'co-morbidities' of obesity. There is necessity for international collaboration to ensure robust data is collected on many basic aspects of nutritional care to guarantee that diet therapy is delivered to the highest standard.
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Estado Nutricional/fisiologia , Fenilcetonúrias/fisiopatologia , Composição Corporal , Proteínas Alimentares/metabolismo , Humanos , Micronutrientes/metabolismo , Fenilalanina/deficiência , Fenilalanina/metabolismoRESUMO
An amendment to this paper has been published and can be accessed via the original article.
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BACKGROUND: Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism caused by deficiency in the enzyme phenylalanine hydroxylase that converts phenylalanine into tyrosine. MAIN BODY: In 2017 the first European PKU Guidelines were published. These guidelines contained evidence based and/or expert opinion recommendations regarding diagnosis, treatment and care for patients with PKU of all ages. This manuscript is a supplement containing the practical application of the dietary treatment. CONCLUSION: This handbook can support dietitians, nutritionists and physicians in starting, adjusting and maintaining dietary treatment.
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Fenilalanina Hidroxilase , Fenilcetonúrias , Dieta , Humanos , Fenilalanina , TirosinaRESUMO
Phenylketonuria is an inborn error of amino acid metabolism that results in severe mental retardation if not treated early and appropriately. The traditional treatment, consisting of a low-phenylalanine diet, is usually difficult to maintain throughout adolescence and adulthood, resulting in undesirable levels of blood phenylalanine and consequent neurotoxicity. The neurotoxicity of phenylalanine is enhanced by its transport mechanism across the blood-brain barrier, which has the highest affinity for phenylalanine compared with the other large neutral amino acids that share the same carrier. The supplementation of large neutral amino acids in phenylketonuric patients has been showing interesting results. Plasma phenylalanine levels can be reduced, which may guarantee important metabolic and clinical benefits to these patients. Although long-term studies are needed to determine the efficacy and safety of large neutral amino acids supplements, the present state of knowledge seems to recommend their prescription to all phenylketonuric adult patients who are non-compliant with the low-phenylalanine diet.
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Aminoácidos Neutros/uso terapêutico , Suplementos Nutricionais , Fenilcetonúrias/dietoterapia , Sistemas de Transporte de Aminoácidos/metabolismo , Aminoácidos Neutros/metabolismo , Barreira Hematoencefálica/metabolismo , Humanos , Modelos BiológicosRESUMO
BACKGROUND: In fructose 1,6 bisphosphatase (FBPase) deficiency, management aims to prevent hypoglycaemia and lactic acidosis by avoiding prolonged fasting, particularly during febrile illness. Although the need for an emergency regimen to avoid metabolic decompensation is well established at times of illness, there is uncertainty about the need for other dietary management strategies such as sucrose or fructose restriction. We assessed international differences in the dietary management of FBPase deficiency. METHODS: A cross-sectional questionnaire (13 questions) was emailed to all members of the Society for the Study of Inborn Errors of Metabolism (SSIEM) and a wide database of inherited metabolic disorder dietitians. RESULTS: Thirty-six centres reported the dietary prescriptions of 126 patients with FBPase deficiency. Patients' age at questionnaire completion was: 1-10y, 46% (n = 58), 11-16y, 21% (n = 27), and >16y, 33% (n = 41). Diagnostic age was: <1y, 36% (n = 46); 1-10y, 59% (n = 74); 11-16y, 3% (n = 4); and >16y, 2% (n = 2). Seventy-five per cent of centres advocated dietary restrictions. This included restriction of: high sucrose foods only (n = 7 centres, 19%); fruit and sugary foods (n = 4, 11%); fruit, vegetables and sugary foods (n = 13, 36%). Twenty-five per cent of centres (n = 9), advised no dietary restrictions when patients were well. A higher percentage of patients aged >16y rather than ≤16y were prescribed dietary restrictions: patients aged 1-10y, 67% (n = 39/58), 11-16y, 63% (n = 17/27) and >16y, 85% (n = 35/41). Patients classified as having a normal fasting tolerance increased with age from 30% in 1-10y, to 36% in 11-16y, and 58% in >16y, but it was unclear if fasting tolerance was biochemically proven. Twenty centres (56%) routinely prescribed uncooked cornstarch (UCCS) to limit overnight fasting in 47 patients regardless of their actual fasting tolerance (37%). All centres advocated an emergency regimen mainly based on glucose polymer for illness management. CONCLUSIONS: Although all patients were prescribed an emergency regimen for illness, use of sucrose and fructose restricted diets with UCCS supplementation varied widely. Restrictions did not relax with age. International guidelines are necessary to help direct future dietary management of FBPase deficiency.
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Deficiência de Frutose-1,6-Difosfatase/dietoterapia , Acidose Láctica/etiologia , Acidose Láctica/prevenção & controle , Estudos Transversais , Carboidratos da Dieta , Suplementos Nutricionais , Jejum , Deficiência de Frutose-1,6-Difosfatase/complicações , Humanos , Hipoglicemia/etiologia , Hipoglicemia/prevenção & controle , Inquéritos e QuestionáriosRESUMO
A study on the incorporation of coal bottom ash from thermoelectric power stations as a substitute material for natural sand in the production of concrete is here presented. The normally coarse, fused, glassy texture of bottom ash makes it an ideal substitute for natural aggregates. The use of bottom ash in concrete presents several technical challenges: the physical and mineralogical characteristics of the bottom ash; the effect on water demand and the participation on cements hydratation. In the production of the concrete, substitutions in volume were used. Two different ways to employ bottom ash were used to make up the mix proportions: one considering the natural humidity present in the porous particles and the other not considering it, seeking to maintain the same strength. These considerations are fundamental given that the process of bottom ash extraction is carried out through moisture. Mechanical tests by compressive strength were performed and the elastic modulus was determined. An analysis of the influence of bottom ash in the formation of pores was carried out through tests for the water loss by air drying and water uptake by capillary absorption. The results show that the higher the bottom ash contents in the concrete, the worse the performance regarding moisture transport. However, for one bottom ash concrete type, the mechanical properties were maintained.
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Carbono/química , Conservação dos Recursos Naturais , Materiais de Construção , Resíduos Industriais , Material Particulado/química , Centrais Elétricas , Adsorção , Carvão Mineral , Cinza de Carvão , Força Compressiva , Elasticidade , Etanol/química , Resíduos Industriais/análise , Água/químicaRESUMO
Cyclodextrins and cyclodextrins-modified molecules have interesting and appealing properties due to their capacity to host components that are normally insoluble or poorly soluble in water. In this work, we investigate the interaction of a ß-cyclodextrin polymer (poly-ß-CD) with λ-DNA. The polymers are obtained by the reaction of ß-CD with epichlorohydrin in alkaline conditions. We have used optical tweezers to characterize the changes of the mechanical properties of DNA molecules by increasing the concentration of poly-ß-CD in the sample. The physical chemistry of the interaction is then deduced from these measurements by using a recently developed quenched-disorder statistical model. It is shown that the contour length of the DNA does not change in the whole range of poly-ß-CD concentration (<300µM). On the other hand, significant alterations were observed in the persistence length that identifies two binding modes corresponding to the clustering of â¼2.6 and â¼14 polymer molecules along the DNA double helix, depending on the polymer concentration. Comparing these results with the ones obtained for monomeric ß-CD, it was observed that the concentration of CD that alters the DNA persistence length is considerably smaller when in the polymeric form. Also, the binding constant of the polymer-DNA interaction is three orders of magnitude higher than the one found for native (monomeric) ß-CD. These results show that the polymerization of the ß-CD strongly increases its binding affinity to the DNA molecule. This property can be wisely used to modulate the binding of cyclodextrins to the DNA double helix.