Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 282
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Foot Ankle Surg ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-39112114

RESUMO

BACKGROUND: Chronic ankle instability is frequent complication following ankle sprains. Anatomical reconstruction of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) with a gracilis autograft is a validated reconstruction technique. The signal-to-noise quotient ankle (SNQA) score evaluates graft maturation with MRI and has been shown to be reproducible and reliable. The goal of this study was to evaluate the process of ligamentization of the anatomical reconstruction of the ankle using the SNQA. The hypothesis was that the SNQA signal of the ATFL and the CFL would decrease over time. METHODS: A prospective cohort of patients who underwent arthroscopic anatomical ATFL-CFL reconstruction was included. All patients underwent a follow-up MRI examination 3, 6. and 12 months after surgery and the SNQA score was determined. RESULTS: Twenty consecutive patients were included. The SNQA score decreased significantly over time for the ATFL (p = 0.001), the CFL (p < 0.001) and for the fibular bone tunnel-graft interface (p = 0.02). The SNQA scores of the ATFL were significantly higher than those of the CFL at 3 months (p = 0.01), 6 months (p = 0.003) and 12 months (p < 0.001), and then those of the fibular tunnel-graft interface at 12 months (p = 0.003). There was no difference in the SNQA score between the CFL and in the fibular graft-bone tunnel interface at any of the follow up periods. CONCLUSION: There is a process of graft maturation following anatomical ATFL and CFL reconstruction over time, which is faster for the CFL than for the ATFL during the first year. LEVEL OF EVIDENCE: II.

2.
Knee Surg Sports Traumatol Arthrosc ; 31(11): 4961-4968, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37612477

RESUMO

PURPOSE: The return to sport is one of the main goals following Achilles tendon tear repair. Several psychological factors influence the return to sport after a sports injury. The traditional tools to assess the return to sport do not take into account psychological factors. The ankle ligament reconstruction-return to sport injury (ALR-RSI), validated for ankle instability, is a score to evaluate psychological readiness to return to sport. The goal of this study was to validate the ALR-RSI score for the assessment of the readiness to return to sport after Achilles tendon repair. METHODS: The ALR-RSI score, adapted from the anterior cruciate ligament-return to sport injury (ACL-RSI) score used following knee ligament reconstruction, was validated according to the international COSMIN methodology. Patients operated for Achilles tendon repair responded to the questionnaire during the rehabilitation period. The EFAS, FAAM and VISA-A scores were used as reference questionnaires. RESULTS: A total of 50 patients were included. The ALR-RSI score was strongly (r > 0.5) correlated to the EFAS score: r = 0.68 [0.50-0.80] the FAMM sport score: r = 0.7 [0.52-0.84] the FAAM AVQ score (r = 0.6 [0.35-0.78]), and the VISA-A score (r = 0.54 [0.26-0.76]). The discriminant validity was good with the ALR-RSI, which was significantly lower in the patients that did not return to sport: 60.7 (40-81.4) compared to those that did: 83.2 (64.3-100) p = 0.001. Reproducibility was excellent with an intra-class correlation coefficient ρ of 0.99 [097-1.00]. The internal consistency was excellent (alpha coefficient = 0.95). CONCLUSION: The ALR-RSI score provides a valid, reproducible assessment of the psychological readiness to return to sport in patients who undergo surgical Achilles tendon suture repair. LEVEL OF EVIDENCE: III.


Assuntos
Tendão do Calcâneo , Traumatismos do Tornozelo , Lesões do Ligamento Cruzado Anterior , Reconstrução do Ligamento Cruzado Anterior , Humanos , Volta ao Esporte/psicologia , Tornozelo/cirurgia , Lesões do Ligamento Cruzado Anterior/reabilitação , Tendão do Calcâneo/cirurgia , Reprodutibilidade dos Testes , Reconstrução do Ligamento Cruzado Anterior/reabilitação , Ligamento Cruzado Anterior/cirurgia , Traumatismos do Tornozelo/cirurgia
3.
Eur Arch Otorhinolaryngol ; 278(7): 2613-2618, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33420839

RESUMO

OBJECTIVES: Guidance set out by Scottish Intercollegiate Guidelines Network (SIGN) sought to restrict the frequency of elective tonsillectomy in reaction to the recognised and substantial risks of the procedure, namely pain and bleeding. With stricter criteria in place before a patient can undergo tonsillectomy, patients must endure more episodes of tonsillitis than was previously the case. The cost of managing tonsillitis and its complications as an inpatient is substantial to the NHS and also to the economy as a whole in missed work days. The authors sought to establish if the reduced rate of tonsillectomy performed had any effect on the rate of acute hospital admission for tonsillitis or the associated abscesses-peritonsillar, parapharyngeal and retropharyngeal. METHODS: A retrospective multi-centre study reviewed admission data across a 4-year period. The rate of tonsillectomies performed for recurrent tonsillitis across four trusts in Mid-Essex was compared with the number of admissions for tonsillitis, peritonsillar, parapharyngeal and retropharyngeal abscesses. National hospital episode statistics data over a 5-year period was also analysed. RESULTS: For the regional data in 2015, 979 tonsillectomies were performed across the four centres, reducing to 875 in 2018. There was no trend in the rates of acute tonsillitis requiring admission but the rates of peritonsillar abscess increased from 156 to 192 cases per year in the same period. This correlation was found not to be statistically significant in the measured sample size. The National hospital episode statistics data showed a significant correlation between tonsillectomy rates and admissions from complications of tonsillitis as well as the associated abscesses. CONCLUSION: This study shows that the reduced tonsillectomy rate was correlated with an increased number of admissions with peritonsillar abscess regionally. Nationally reduced tonsillectomy rate is significantly associated with increased admissions with tonsillitis and all its complications. A decreased rate of tonsillectomy may be increasing the rate of serious tonsillitis. This has an impact on patient morbidity, an increasing financial burden on the NHS and the UK economy.


Assuntos
Abscesso Peritonsilar , Tonsilectomia , Tonsilite , Inglaterra/epidemiologia , Humanos , Abscesso Peritonsilar/epidemiologia , Abscesso Peritonsilar/cirurgia , Estudos Retrospectivos , Tonsilite/epidemiologia , Tonsilite/cirurgia
4.
Compr Psychiatry ; 96: 152128, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31715335

RESUMO

BACKGROUND: Antenatal maternal psychological distress is common in low and middle-income countries (LMIC), but there is a dearth of research on its effect on birth and developmental outcomes in these settings, particularly in Sub-Saharan Africa. This study set out to identify risk factors for antenatal maternal psychological distress and determine whether antenatal maternal psychological distress was associated with infant birth and developmental outcomes, using data from the Drakenstein Child Health Study (DCHS), a birth cohort study in South Africa. METHODS: Pregnant women were enrolled in the DCHS from primary care antenatal clinics. Antenatal maternal psychological distress was measured using the Self-Reporting Questionnaire 20-item (SRQ-20). A range of psychosocial measures, including maternal childhood trauma, depression, and posttraumatic stress disorder (PTSD) were administered. Birth outcomes, including premature birth, weight-for-age z-score and head circumference-for-age z-score, were measured using revised Fenton growth charts. The Bayley III Scales of Infant and Toddler Development was administered at 6 months of age to assess infant development outcomes, including cognitive, language, and motor domains in a subset of n=231. Associations of maternal antenatal psychological distress with psychosocial measures, and with infant birth and developmental outcomes were examined using linear regression models. RESULTS: 961 women were included in this analysis, with 197 (21%) reporting scores indicating the presence of psychological distress. Antenatal psychological distress was associated with maternal childhood trauma, antenatal depression, and PTSD, and inversely associated with partner support. No association was observed between antenatal maternal psychological distress and preterm birth or early developmental outcomes, but antenatal maternal psychological distress was associated with a smaller head circumference at birth (coefficient=-0.30, 95% CI: -0.49; -0.10). CONCLUSION: Antenatal maternal psychological distress is common in LMIC settings and was found to be associated with key psychosocial measures during pregnancy, as well as with adverse birth outcomes, in our study population. These associations highlight the potential value of screening for antenatal maternal psychological distress as well as of developing targeted interventions.


Assuntos
Desenvolvimento Infantil/fisiologia , Complicações na Gravidez/psicologia , Efeitos Tardios da Exposição Pré-Natal/psicologia , Angústia Psicológica , Adulto , Estudos de Coortes , Família , Feminino , Humanos , Lactente , Recém-Nascido , Gravidez , Complicações na Gravidez/diagnóstico , Fatores de Risco , África do Sul , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Transtornos de Estresse Pós-Traumáticos/psicologia , Inquéritos e Questionários , Adulto Jovem
5.
Langmuir ; 35(49): 16101-16110, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31697083

RESUMO

The recent cost-driven transition from silver- to copper-based inks for printing on flexible substrates is connected with new key challenges. Given the high oxidation sensitivity of copper inks before, during, and after the curing process, the conductivity and thereby the device performance can be affected. Strategies to limit or even avoid this drawback include the development of metal organic decomposition (MOD) inks with selected "protective" ligands. In this study, the influence of the ligand on the oxide formation during the ink decomposition process is described using a wide variety of in situ characterization techniques. It is demonstrated that bidentate ligands provide an improved oxidation barrier, although the copper preservation mechanism has its limits: oxygen can interfere in every reduction pathway depending on the curing duration and atmospheric conditions. The generated insights can be applied in the further evolution toward ambient-curable copper MOD inks.

6.
Nanotechnology ; 29(42): 425201, 2018 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-30067231

RESUMO

Silver nanowire networks have demonstrated significant potential as semi-transparent electrodes for various applications. However, for their widespread utilisation in devices, upscaled coating technologies such as screen-printing need to be explored and related to this, the formulation of suitable inks is indispensable. This work contributes to this effort by the synthesis of Ag-NW based formulations. The rheological characteristics that are essential for screen-printing are obtained by the addition of hydrophobically modified cellulose. The electrical and optical characteristics of screen-printed features on PET are compared by a Van der Pauw method and UV-vis spectroscopy. Despite the presence of the cellulose additive, the screen-printed electrodes exhibit a transmittance from 92.8% to 57.3% and a sheet resistance down to 27 Ohm sq-1. Based on the percolation theory in composites, a mathematical expression is presented, which allows the in-depth analysis of the resulting opto-electrical properties. The application potential of the nanowire-containing formulations is finally demonstrated by screen-printing functional, flexible electroluminescent devices.

7.
J Occup Rehabil ; 28(3): 465-474, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-28889328

RESUMO

Objective The Work Role Functioning Questionnaire v2.0 (WRFQ) is an outcome measure linking a persons' health to the ability to meet work demands in the twenty-first century. We aimed to examine the construct validity of the WRFQ in a heterogeneous set of working samples in the Netherlands with mixed clinical conditions and job types to evaluate the comparability of the scale structure. Methods Confirmatory factor and multi-group analyses were conducted in six cross-sectional working samples (total N = 2433) to evaluate and compare a five-factor model structure of the WRFQ (work scheduling demands, output demands, physical demands, mental and social demands, and flexibility demands). Model fit indices were calculated based on RMSEA ≤ 0.08 and CFI ≥ 0.95. After fitting the five-factor model, the multidimensional structure of the instrument was evaluated across samples using a second order factor model. Results The factor structure was robust across samples and a multi-group model had adequate fit (RMSEA = 0.63, CFI = 0.972). In sample specific analyses, minor modifications were necessary in three samples (final RMSEA 0.055-0.080, final CFI between 0.955 and 0.989). Applying the previous first order specifications, a second order factor model had adequate fit in all samples. Conclusion A five-factor model of the WRFQ showed consistent structural validity across samples. A second order factor model showed adequate fit, but the second order factor loadings varied across samples. Therefore subscale scores are recommended to compare across different clinical and working samples.


Assuntos
Nível de Saúde , Inquéritos e Questionários , Avaliação da Capacidade de Trabalho , Adulto , Estudos Transversais , Análise Fatorial , Feminino , Humanos , Seguro , Masculino , Transtornos Mentais/psicologia , Pessoa de Meia-Idade , Modelos Estatísticos , Neoplasias/complicações , Esforço Físico , Médicos , Psicometria , Jornada de Trabalho em Turnos , Universidades , Carga de Trabalho
8.
Psychol Med ; 47(1): 43-51, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27650432

RESUMO

BACKGROUND: There is limited evidence for effective interventions in the treatment of post-traumatic stress symptoms within individuals diagnosed with schizophrenia. Clinicians have concerns about using exposure treatments with this patient group. The current trial was designed to evaluate a 16-session cognitive restructuring programme, without direct exposure, for the treatment of post-traumatic stress symptoms specifically within individuals diagnosed with schizophrenia. METHOD: A multicentre randomized controlled single-blinded trial with assessments at 0 months, 6 months (post-treatment) and 12 months (follow-up) was conducted. A total of 61 participants diagnosed with schizophrenia and exhibiting post-traumatic stress symptoms were recruited. Those randomized to treatment were offered up to 16 sessions of cognitive-behaviour therapy (CBT, including psychoeducation, breathing training and cognitive restructuring) over a 6-month period, with the control group offered routine clinical services. The main outcome was blind rating of post-traumatic stress symptoms using the Clinician Administered PTSD Scale for Schizophrenia. Secondary outcomes were psychotic symptoms as measured by the Positive and Negative Symptom Scale and the Psychotic Symptom Rating Scale. RESULTS: Both the treatment and control groups experienced a significant decrease in post-traumatic stress symptoms over time but there was no effect of the addition of CBT on either the primary or secondary outcomes. CONCLUSIONS: The current trial did not demonstrate any effect in favour of CBT. Cognitive restructuring programmes may require further adaptation to promote emotional processing of traumatic memories within people diagnosed with a psychotic disorder.


Assuntos
Terapia Cognitivo-Comportamental/métodos , Avaliação de Resultados em Cuidados de Saúde , Esquizofrenia/terapia , Transtornos de Estresse Pós-Traumáticos/terapia , Adulto , Comorbidade , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Esquizofrenia/epidemiologia , Método Simples-Cego , Transtornos de Estresse Pós-Traumáticos/epidemiologia
9.
Langmuir ; 33(43): 12267-12275, 2017 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-28967757

RESUMO

We use the corresponding distances method (CDM) to computationally assess the quality of 10 experimentally tested carbon nanotube (CNT) solvents. The CDM produces accurate and high-resolution potential of mean force curves from a single simulation per solvent. The method's very high efficiency allows us to investigate an unprecedented number of solvents in one study. The simulation results indicate that none of the tested molecules are solvents in the thermodynamic sense; instead, they are dispersants preventing reaggregation of already dispersed CNTs. We find that the dispersion free energy barrier correlates very well with the experimentally measured performance of the dispersants; i.e., the simulations place the solvents in the correct performance order. Our analysis of the structure-function relationship rationalizes this order.

10.
Nanotechnology ; 28(21): 215202, 2017 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-28471754

RESUMO

Integration of electronic circuit components onto flexible materials such as plastic foils, paper and textiles is a key challenge for the development of future smart applications. Therefore, conductive metal features need to be deposited on temperature sensitive substrates in a fast and straightforward way. The feasibility of these emerging (nano-) electronic technologies depends on the availability of well-designed deposition techniques and on novel functional metal inks. As ultrasonic spray coating (USSC) is one of the most promising techniques to meet the above requirements, innovative metal organic decomposition (MOD) inks are designed to deposit silver features on plastic foils. Various amine ligands were screened and their influence on the ink stability and the characteristics of the resulting metal depositions were evaluated to determine the optimal formulation. Eventually, silver layers with excellent performance in terms of conductivity (15% bulk silver conductivity), stability, morphology and adhesion could be obtained, while operating in a very low temperature window of 70 °C-120 °C. Moreover, the optimal deposition conditions were determined via an in-depth analysis of the ultrasonically sprayed silver layers. Applying these tailored MOD inks, the USSC technique enabled smooth, semi-transparent silver layers with a tunable thickness on large areas without time-consuming additional sintering steps after deposition. Therefore, this novel combination of nanoparticle-free Ag-inks and the USSC process holds promise for high throughput deposition of highly conductive silver features on heat sensitive substrates and even 3D objects.

11.
Phys Chem Chem Phys ; 19(40): 27866-27877, 2017 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-28991959

RESUMO

A combined experimental and first-principles study is performed to study the origin of conductivity in ZnO:Al nanoparticles synthesized under controlled conditions via a reflux route using benzylamine as a solvent. The experimental characterization of the samples by Raman, nuclear magnetic resonance (NMR) and conductivity measurements indicates that upon annealing in nitrogen, the Al atoms at interstitial positions migrate to the substitutional positions, creating at the same time Zn interstitials. We provide evidence for the fact that the formed complex of AlZn and Zni corresponds to the origin of the Knight shifted peak (KS) we observe in 27Al NMR. As far as we know, the role of this complex has not been discussed in the literature to date. However, our first-principles calculations show that such a complex is indeed energetically favoured over the isolated Al interstitial positions. In our calculations we also address the charge state of the Al interstitials. Further, Zn interstitials can migrate from AlZn and possibly also form Zn clusters, leading to the observed increased conductivity.

12.
Ergonomics ; 59(2): 310-24, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26241633

RESUMO

This study examined associations of chronotype and age with shift-specific assessments of main sleep duration, sleep quality and need for recovery in a cross-sectional study among N = 261 industrial shift workers (96.6% male). Logistic regression analyses were used, adjusted for gender, lifestyle, health, nap behaviour, season of assessment and shift schedule. Shift workers with latest versus earliest chronotype reported a shorter sleep duration (OR 11.68, 95% CI 3.31-41.17) and more awakenings complaints (OR 4.84, 95% CI 4.45-11.92) during morning shift periods. No associations were found between chronotype, sleep and need for recovery during evening and night shift periods. For age, no associations were found with any of the shift-specific outcome measures. The results stress the importance of including the concept of chronotype in shift work research and scheduling beyond the concept of age. Longitudinal research using shift-specific assessments of sleep and need for recovery are needed to confirm these results. PRACTITIONER SUMMARY: Chronotype seems to better explain individual differences in sleep than age. In view of ageing societies, it might therefore be worthwhile to further examine the application of chronotype for individualised shift work schedules to facilitate healthy and sustainable employment.


Assuntos
Fatores Etários , Relógios Circadianos/fisiologia , Recuperação de Função Fisiológica/fisiologia , Sono/fisiologia , Tolerância ao Trabalho Programado/fisiologia , Adulto , Estudos Transversais , Feminino , Humanos , Indústrias , Masculino , Pessoa de Meia-Idade , Doenças Profissionais/etiologia , Doenças Profissionais/fisiopatologia , Transtornos do Sono do Ritmo Circadiano/etiologia , Transtornos do Sono do Ritmo Circadiano/fisiopatologia , Fatores de Tempo , Vigília
14.
Ergonomics ; 58(12): 1927-38, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26074172

RESUMO

The objectives of this study were to (1) examine whether need for recovery differs between workers (i) not on-call, (ii) on-call but not called and (iii) on-call and called, and (2) investigate the associations between age, health, work and social characteristics with need for recovery for the three scenarios (i-iii). Cross-sectional data of N = 169 Dutch distal on-call workers were analysed with multivariate logistic regression. Need for recovery differed significantly between the three scenarios (i-iii), with lowest need for recovery for scenario (i) 'not on-call' and highest need for recovery for scenario (iii) 'on-call and called'. Poor mental health and high work-family interference were associated with higher need for recovery in all three scenarios (i-iii), whereas high work demands was only associated with being on-call (ii and iii). The results suggest that the mere possibility of being called affects the need for recovery, especially in workers reporting poor mental health, high-work demands and work-family interference. Practitioner summary: On-call work is a scarcely studied but demanding working time arrangement. We examined need for recovery and its associations with age, health, work and social characteristics among distal on-call workers. The results suggest that the mere possibility of being called can affect worker well-being and need for recovery.


Assuntos
Avaliação das Necessidades , Sono , Tolerância ao Trabalho Programado , Equilíbrio Trabalho-Vida , Carga de Trabalho , Adulto , Estudos Transversais , Humanos , Modelos Logísticos , Masculino , Saúde Mental , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Admissão e Escalonamento de Pessoal
15.
Sci Rep ; 14(1): 21036, 2024 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-39251766

RESUMO

Fish domestication progresses through five levels: from the initial acclimatization to captivity (Level 1), to the life cycle completion in captivity (Level 4), and even to the implementation of selective breeding programs (Level 5). Domestication leads to phenotypic changes over generations, sometimes from the very first generation. Behavioral traits are among the first to change. However, in fish, potential behavioral changes during early domestication have been little studied. Therefore, we studied potential behavioral changes among early and advanced levels of domestication in a model species, the zebrafish (Danio rerio), using a mirror test experiment, commonly used to assess traits involved in activity, aggressiveness, and stress in this species. We compared these traits between wild zebrafish in captivity (F0; Level 1), the first generation of their captive-born offspring (F1; Level 4), and three laboratory strains (AB, TU, and WIK; Level 5). Each fish was individually filmed and tracked using an automated procedure for 5 min. Nine behavioral traits and one activity-related trait were characterized for each individual based on the movements and positioning of the fish. We applied a principal component analysis (PCA) and tested the significance of potential differences between groups using an analysis of similarities (ANOSIM). We applied an indicator value analysis (IndVal) to determine which traits were most expressed by each group. We detected differences between groups and across domestication levels. More specifically, we highlighted differentiations between different levels of domestication (e.g. between F1, AB, TU, and WIK) as early as the beginning of the domestication process (i.e. F0 vs. F1), but also within the same level of domestication (i.e. AB vs. TU). Based on PCA and IndVal, (i) F0 and F1 tended to show stronger expression of stress-related traits than the other groups, (ii) F0 was more active than others, and (iii) TU was more aggressive than AB. Our results confirmed that domestication can change fish behavior, even in the first generation born in captivity, although these modifications remain limited. In contrast, we did not observe any general trends correlated with domestication levels, given that AB and TU diverged in their aggressiveness levels, and WIK differed only from F1. This result needs to be generalized to other species but also considered for domestication for aquaculture. If future studies confirm that the changes observed at the beginning of the domestication process remain limited and that there is no consistent evolutionary trend across generations in fish, this would highlight the crucial importance of selecting the right species from the outset of domestication. It would also emphasize the need to design selective breeding programs that shape fish stocks with the most desirable characteristics. To our knowledge, this study is one of the few to examine the behavior of wild zebrafish alongside laboratory strains, offering a unique insight into the early stages of domestication.


Assuntos
Comportamento Animal , Domesticação , Peixe-Zebra , Animais , Peixe-Zebra/fisiologia , Comportamento Animal/fisiologia , Agressão/fisiologia , Estresse Fisiológico , Feminino , Masculino , Gravação em Vídeo , Fenótipo
16.
Bioresour Technol ; 396: 130417, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38316229

RESUMO

Global food waste emits substantial quantities of nitrogen to the environment (6.3 Mtons annually), chicken feather (CF) waste is a major contributor to this. Pyrolysis, in particular co-pyrolysis of nitrogen-rich and lignocellulosic waste streams is a promising strategy to improve the extent of pyrolytic nitrogen retention by incorporating nitrogen in its solid biochar structure. As such, this biochar can serve as a precursor for nitrogen-enriched activated carbons for application in supercapacitors. Therefore, this study investigates the co-pyrolysis of CF with macadamia nut shells (MNS) to create nitrogen-rich activated carbons. Co-pyrolysis increased nitrogen retention during pyrolysis from 9 % to 18 % compared to CF mono-pyrolysis, while the porosity was maintained. After removing undesirable inorganic impurities by dilute acid washing, this led to a specific capacitance of 21F/g using a scan rate of 20 mV/s. Finally, cycling stability tests demonstrated good stability with 73 % capacitance retention after 10 000 cycles.


Assuntos
Carvão Vegetal , Macadamia , Eliminação de Resíduos , Animais , Galinhas , Nitrogênio/química , Plumas , Alimentos , Pirólise , Eletrodos
17.
Diabetologia ; 56(9): 2010-20, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23783352

RESUMO

AIMS/HYPOTHESIS: Sirtuin 1 (SIRT1) has emerged as a key metabolic regulator of glucose homeostasis and insulin secretion. Enhanced SIRT1 activity has been shown to be protective against diabetes, although the mechanisms remain largely unknown. The aim of this study was to determine how SIRT1 regulates insulin secretion in the pancreatic beta cell. METHODS: Pancreatic beta cell-specific Sirt1 deletion was induced by tamoxifen injection in 9-week-old Pdx1CreER:floxSirt1 mice (Sirt1BKO). Controls were injected with vehicle. Mice were assessed metabolically via glucose challenge, insulin tolerance tests and physical variables. In parallel, Sirt1 short interfering RNA-treated MIN6 cells (SIRT1KD) and isolated Sirt1BKO islets were used to investigate the effect of SIRT1 inactivation on insulin secretion and gene expression. RESULTS: OGTTs showed impaired glucose disposal in Sirt1BKO mice due to insufficient insulin secretion. Isolated Sirt1BKO islets and SIRT1KD MIN6 cells also exhibited impaired glucose-stimulated insulin secretion. Subsequent analyses revealed impaired α-ketoisocaproic acid-induced insulin secretion and attenuated glucose-induced Ca(2+) influx, but normal insulin granule exocytosis in Sirt1BKO beta cells. Microarray studies revealed a large cluster of mitochondria-related genes, the expression of which was dysregulated in SIRT1KD MIN6 cells. Upon further analysis, we demonstrated an explicit defect in mitochondrial function: the inability to couple nutrient metabolism to mitochondrial membrane hyperpolarisation and reduced oxygen consumption rates. CONCLUSIONS/INTERPRETATION: Taken together, these findings indicate that in beta cells the deacetylase SIRT1 regulates the expression of specific mitochondria-related genes that control metabolic coupling, and that a decrease in beta cell Sirt1 expression impairs glucose sensing and insulin secretion.


Assuntos
Glucose/metabolismo , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Sirtuína 1/metabolismo , Animais , Western Blotting , Feminino , Imuno-Histoquímica , Masculino , Potencial da Membrana Mitocondrial/fisiologia , Camundongos , Microscopia Eletrônica de Transmissão , Reação em Cadeia da Polimerase em Tempo Real , Sirtuína 1/genética
18.
Diabetologia ; 55(2): 358-71, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22075915

RESUMO

AIMS/HYPOTHESIS: Using a novel directed differentiation protocol, we recently generated up to 25% insulin-producing cells from human embryonic stem cells (hESCs) (insulin(+) cells). At this juncture, it was important to functionally and molecularly characterise these hESC-derived insulin(+) cells and identify key differences and similarities between them and primary beta cells. METHODS: We used a new reporter hESC line with green fluorescent protein (GFP) cDNA targeted to the INS locus by homologous recombination (INS (GFP/w)) and an untargeted hESC line (HES2). INS (GFP/w) allowed efficient identification and purification of GFP-producing (INS:GFP(+)) cells. Insulin(+) cells were examined for key features of adult beta cells using microarray, quantitative PCR, secretion assays, imaging and electrophysiology. RESULTS: Immunofluorescent staining showed complete co-localisation of insulin with GFP; however, cells were often multihormonal, many with granules containing insulin and glucagon. Electrophysiological recordings revealed variable K(ATP) and voltage-gated Ca(2+) channel activity, and reduced glucose-induced cytosolic Ca(2+) uptake. This translated into defective glucose-stimulated insulin secretion but, intriguingly, appropriate glucagon responses. Gene profiling revealed differences in global gene expression between INS:GFP(+) cells and adult human islets; however, INS:GFP(+) cells had remarkably similar expression of endocrine-lineage transcription factors and genes involved in glucose sensing and exocytosis. CONCLUSIONS/INTERPRETATION: INS:GFP(+) cells can be purified from differentiated hESCs, providing a superior source of insulin-producing cells. Genomic analyses revealed that INS:GFP(+) cells collectively resemble immature endocrine cells. However, insulin(+) cells were heterogeneous, a fact that translated into important functional differences within this population. The information gained from this study may now be used to generate new iterations of functioning beta cells that can be purified for transplant.


Assuntos
Células-Tronco Embrionárias/citologia , Células Secretoras de Insulina/citologia , Insulina/metabolismo , Trifosfato de Adenosina/química , Adulto , Animais , Cálcio/metabolismo , Eletrofisiologia/métodos , Proteínas de Fluorescência Verde/metabolismo , Humanos , Ilhotas Pancreáticas/citologia , Camundongos , Microscopia de Fluorescência/métodos , Análise de Sequência com Séries de Oligonucleotídeos , Pâncreas/embriologia , Potássio/metabolismo , Fatores de Tempo
19.
Am J Physiol Endocrinol Metab ; 302(9): E1084-96, 2012 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-22338079

RESUMO

Genomewide association studies have linked a polymorphism in the zinc transporter 8 (Znt8) gene to higher risk of developing type 2 diabetes. Znt8 is highly expressed in pancreatic ß-cells where it is involved in the regulation of zinc transport into granules. However, Znt8 is also expressed in other tissues including α-cells, where its function is as yet unknown. Previous work demonstrated that mice lacking Znt8 globally were more susceptible to diet-induced obesity (Lemaire et al., Proc Natl Acad Sci USA 106: 14872-14877, 2009; Nicolson et al., Diabetes 58: 2070-2083, 2009). Therefore, the main goal of this study was to examine the physiological impact of ß-cell-specific Znt8 deficiency in mice during high-fat high-calorie (HFHC) diet feeding. For these studies, we used ß-cell-specific Znt8 knockout (Ins2Cre:Znt8loxP/loxP) and whole body Znt8 knockout (Cre-:Znt8(-/-)) mice placed on a HFHC diet for 16 wk. Ins2Cre:Znt8loxP/loxP mice on HFHC diet had similar body weights throughout the study but displayed impaired insulin biosynthesis and secretion and were glucose intolerant compared with littermate control Ins2Cre mice. In contrast, Cre-:Znt8(-/-) mice became remarkably obese, hyperglycemic, hyperinsulinemic, insulin resistant, and glucose intolerant compared with littermate control Cre- mice. These data show that ß-cell Znt8 alone does not considerably aggravate weight gain and glucose intolerance during metabolic stress imposed by an HFHC diet. However, global loss of Znt8 is involved in exacerbating diet-induced obesity and resulting insulin resistance, and this may be due to the loss of Znt8 activity in a tissue other than the ß-cell. Thus, our data suggest that Znt8 contributes to the risk of developing type 2 diabetes through ß-cell- and non-ß-cell-specific effects.


Assuntos
Proteínas de Transporte de Cátions/fisiologia , Dieta Hiperlipídica , Resistência à Insulina/fisiologia , Células Secretoras de Insulina/metabolismo , Obesidade/metabolismo , Análise de Variância , Animais , Glicemia/metabolismo , Proteínas de Transporte de Cátions/deficiência , Proteínas de Transporte de Cátions/genética , Ingestão de Energia , Resistência à Insulina/genética , Masculino , Análise por Pareamento , Camundongos , Camundongos Knockout , Obesidade/genética , Estresse Fisiológico/fisiologia , Distribuição Tecidual , Transportador 8 de Zinco
20.
Euro Surveill ; 17(31)2012 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-22874457

RESUMO

We posted a survey on the Union of European Football Associations (UEFA)'s EURO 2012 Facebook profile to evaluate whether public health travel advice, specifically on the importance of measles vaccination,reached fans attending EURO 2012. Responses suggested that these messages were missed by 77% of fans. Social networks could serve as innovative platforms to conduct surveys, enabling rapid access to target populations at low cost and could be of use during upcoming mass gatherings such as the Olympics.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Internet , Sarampo/prevenção & controle , Saúde Pública , Futebol , Rede Social , Viagem , Estudos Transversais , Feminino , Inquéritos Epidemiológicos , Humanos , Imunização/estatística & dados numéricos , Masculino , Vacina contra Sarampo/administração & dosagem , Polônia , Inquéritos e Questionários , Ucrânia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA