Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 139
Filtrar
1.
Nature ; 587(7833): 219-224, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33177670

RESUMO

Soft machines are a promising design paradigm for human-centric devices1,2 and systems required to interact gently with their environment3,4. To enable soft machines to respond intelligently to their surroundings, compliant sensory feedback mechanisms are needed. Specifically, soft alternatives to strain gauges-with high resolution at low strain (less than 5 per cent)-could unlock promising new capabilities in soft systems. However, currently available sensing mechanisms typically possess either high strain sensitivity or high mechanical resilience, but not both. The scarcity of resilient and compliant ultra-sensitive sensing mechanisms has confined their operation to laboratory settings, inhibiting their widespread deployment. Here we present a versatile and compliant transduction mechanism for high-sensitivity strain detection with high mechanical resilience, based on strain-mediated contact in anisotropically resistive structures (SCARS). The mechanism relies upon changes in Ohmic contact between stiff, micro-structured, anisotropically conductive meanders encapsulated by stretchable films. The mechanism achieves high sensitivity, with gauge factors greater than 85,000, while being adaptable for use with high-strength conductors, thus producing sensors resilient to adverse loading conditions. The sensing mechanism also exhibits high linearity, as well as insensitivity to bending and twisting deformations-features that are important for soft device applications. To demonstrate the potential impact of our technology, we construct a sensor-integrated, lightweight, textile-based arm sleeve that can recognize gestures without encumbering the hand. We demonstrate predictive tracking and classification of discrete gestures and continuous hand motions via detection of small muscle movements in the arm. The sleeve demonstration shows the potential of the SCARS technology for the development of unobtrusive, wearable biomechanical feedback systems and human-computer interfaces.


Assuntos
Retroalimentação Sensorial , Maleabilidade , Robótica/instrumentação , Robótica/métodos , Interface Usuário-Computador , Dispositivos Eletrônicos Vestíveis , Mãos/fisiologia , Humanos , Movimento (Física) , Movimento , Têxteis
2.
HIV Med ; 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38858222

RESUMO

INTRODUCTION: Long-acting injectable cabotegravir + rilpivirine (CAB + RPV LAI) was approved for use in virally suppressed adults in the England and Wales national health service in November 2021. We describe a service evaluation of delivery processes and outcomes in 12 clinics. METHODS: Centres populated a database using information from local policies and clinical records. Services were asked to describe approval processes, clinic pathways, and adherence to national guidelines. Additional data were collected on reasons for regimen choice, treatment discontinuations, and management of viraemia. RESULTS: In total, 518 adults from 12 clinics were approved for CAB + RPV LAI between February 2022 and December 2023. Of the 518 people approved for CAB + RPV LAI, 423 received at least one injection. Median duration on CAB + RPV was 7.5 months (interquartile range 3.7-11.3). In total, 97% of injections were administered within the ±7-day window. Virological failure occurred in 0.7%, and 6% discontinued CAB + RPV. CONCLUSION: In this large UK-based cohort, robust approval processes and clinic protocols facilitated on-time injections and low rates of both discontinuation and virological failure.

3.
Proc Natl Acad Sci U S A ; 115(36): 9008-9013, 2018 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-30126991

RESUMO

Ligaments serve as compliant connectors between hard tissues. In that role, they function under various load regimes and directions. The 3D structure of ligaments is considered to form as a uniform entity that changes due to function. The periodontal ligament (PDL) connects the tooth to the bone and sustains different types of loads in various directions. Using the PDL as a model, employing a fabricated motorized setup in a microCT, we demonstrate that the fibrous network structure within the PDL is not uniform, even before the tooth becomes functional. Utilizing morphological automated segmentation methods, directionality analysis, as well as second harmonic generation imaging, we find high correlation between blood vessel distribution and fiber density. We also show a structural feature in a form of a dense collar around the neck of the tooth as well as a preferred direction of the fibrous network. Finally, we show that the PDL develops as a nonuniform structure, with an architecture designed to sustain specific types of load in designated areas. Based on these findings, we propose that ligaments in general should be regarded as nonuniform entities, structured already at developmental stages for optimal functioning under variable load regimes.


Assuntos
Ligamento Periodontal/diagnóstico por imagem , Dente/diagnóstico por imagem , Microtomografia por Raio-X , Animais , Camundongos , Camundongos Transgênicos , Ligamento Periodontal/irrigação sanguínea , Ligamento Periodontal/metabolismo , Dente/irrigação sanguínea , Dente/metabolismo
4.
Br J Nutr ; 124(7): 701-708, 2020 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-32312337

RESUMO

Fish-oil supplements are marketed as enhancing intelligence and cognitive performance. However, empirical data concerning the utility of these products in healthy term infants are mixed, particularly with respect to lasting effects into childhood. We evaluated whether fish-oil supplementation during infancy leads to better neurocognitive/behavioural development at 6 years. We conducted a double-blind randomised controlled trial of supplementation with n-3 long-chain PUFA in 420 healthy term infants. Infants received either fish oil (containing at least 250 mg DHA and at least 60 mg EPA) or placebo (olive oil) daily from birth to 6 months of age. Neurodevelopmental follow-up was conducted at a mean age of 6 years (sd 7 months), whereby 335 children were assessed for language, executive functioning, global intelligence quotient and behaviour. No significant differences were observed between the groups for the main neurocognitive outcomes. However in parent-report questionnaire, fish-oil supplementation was associated with negative externalising (P = 0·035, d = 0·24) and oppositional/defiant behaviour (P = 0·006, d = 0·31), particularly in boys (P = 0·01, d = 0·45; P = 0·004, d = 0·40). Our results provide evidence that fish-oil supplementation to predominantly breast-fed infants confers no significant cognitive or behavioural benefit to children at 6 years.


Assuntos
Desenvolvimento Infantil/efeitos dos fármacos , Cognição/efeitos dos fármacos , Suplementos Nutricionais , Ácidos Graxos Ômega-3/administração & dosagem , Óleos de Peixe/administração & dosagem , Aleitamento Materno , Criança , Método Duplo-Cego , Função Executiva/efeitos dos fármacos , Feminino , Seguimentos , Humanos , Lactente , Fenômenos Fisiológicos da Nutrição do Lactente , Recém-Nascido , Testes de Inteligência , Masculino , Testes de Estado Mental e Demência , Transtornos do Neurodesenvolvimento/etiologia , Transtornos do Neurodesenvolvimento/prevenção & controle , Azeite de Oliva/administração & dosagem
5.
Adv Funct Mater ; 29(7)2019 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-31372108

RESUMO

Fluidic soft sensors have been widely used in wearable devices for human motion capturing. However, thus far, the biocompatibility of the conductive liquid, the linearity of the sensing signal, and the hysteresis between the loading and release processes have limited the sensing quality as well as the applications of these sensors. In this paper, silicone based strain and force sensors composed of a novel biocompatible conductive liquid (potassium iodide and glycerol solution) are introduced. The strain sensors exhibit negligible hysteresis up to 5 Hz, with a gauge factor of 2.2 at 1 Hz. The force sensors feature a novel multi-functional layered structure, with micro-cylinder-filled channels to achieve high linearity, low hysteresis (5.3% hysteresis at 1 Hz), and good sensitivity (100% resistance increase at a 5 N load). The sensors' gauge factors are stable at various temperatures and humidity levels. These bio-compatible, low hysteresis, and high linearity sensors are promising for safe and reliable diagnostic devices, wearable motion capture, and compliant human-computer interfaces.

6.
Inorg Chem ; 58(16): 10837-10845, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31386356

RESUMO

Metal-organic framework nanosheets (MONs) are attracting increasing attention as a diverse class of two-dimensional materials derived from metal-organic frameworks (MOFs). The principles behind the design of layered MOFs that can readily be exfoliated to form nanosheets, however, remain poorly understood. Here we systematically investigate an isoreticular series of layered MOFs functionalized with alkoxy substituents in order to understand the effect of substituent alkyl chain length on the structure and properties of the resulting nanosheets. A series of 2,5-alkoxybenzene-1,4-dicarboxylate ligands (O2CC6H2(OR)2CO2, R = methyl-pentyl, 1-5, respectively) was used to synthesize copper paddle-wheel MOFs. Rietveld and Pawley fitting of powder diffraction patterns for compounds Cu(3-5)(DMF) showed they adopt an isoreticular series with two-dimensional connectivity in which the interlayer distance increases from 8.68 Å (R = propyl) to 10.03 Å (R = pentyl). Adsorption of CO2 by the MOFs was found to increase from 27.2 to 40.2 cm3 g-1 with increasing chain length, which we attribute to the increasing accessible volume associated with increasing unit-cell volume. Ultrasound was used to exfoliate the layered MOFs to form MONs, with shorter alkyl chains resulting in higher concentrations of exfoliated material in suspension. The average height of MONs was investigated by AFM and found to decrease from 35 ± 26 to 20 ± 12 nm with increasing chain length, with the thinnest MONs observed being only 5 nm, corresponding to five framework layers. These results indicate that careful choice of ligand functionalities can be used to tune nanosheet structure and properties, enabling optimization for a variety of applications.

7.
Int Psychogeriatr ; 31(4): 513-525, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30277188

RESUMO

ABSTRACTBackground:This study investigated the characteristics of subjective memory complaints (SMCs) and their association with current and future cognitive functions. METHODS: A cohort of 209 community-dwelling individuals without dementia aged 47-90 years old was recruited for this 3-year study. Participants underwent neuropsychological and clinical assessments annually. Participants were divided into SMCs and non-memory complainers (NMCs) using a single question at baseline and a memory complaints questionnaire following baseline, to evaluate differential patterns of complaints. In addition, comprehensive assessment of memory complaints was undertaken to evaluate whether severity and consistency of complaints differentially predicted cognitive function. RESULTS: SMC and NMC individuals were significantly different on various features of SMCs. Greater overall severity (but not consistency) of complaints was significantly associated with current and future cognitive functioning. CONCLUSIONS: SMC individuals present distinctive features of memory complaints as compared to NMCs. Further, the severity of complaints was a significant predictor of future cognition. However, SMC did not significantly predict change over time in this sample. These findings warrant further research into the specific features of SMCs that may portend subsequent neuropathological and cognitive changes when screening individuals at increased future risk of dementia.


Assuntos
Cognição , Disfunção Cognitiva/diagnóstico , Avaliação Geriátrica/métodos , Transtornos da Memória , Testes Neuropsicológicos , Idoso , Autoavaliação Diagnóstica , Feminino , Humanos , Vida Independente/estatística & dados numéricos , Masculino , Transtornos da Memória/diagnóstico , Transtornos da Memória/epidemiologia , Transtornos da Memória/psicologia , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Índice de Gravidade de Doença , Austrália Ocidental/epidemiologia
8.
Chemistry ; 24(68): 17986-17996, 2018 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-30222223

RESUMO

The modular structure of metal-organic framework nanosheets (MONs) provides a convenient route to creating two-dimensional materials with readily tuneable surface properties. Here, the liquid exfoliation of two closely related layered metal-organic frameworks functionalised with either methoxy-propyl (1) or pentyl (2) pendent groups intended to bestow either hydrophilic or hydrophobic character to the resulting nanosheets is reported. Exfoliation of the two materials in a range of different solvents highlighted significant differences in their dispersion properties, as well as their molecular and nanoscopic structures. Exchange or loss of solvent was found to occur at the labile axial position of the paddle-wheel based MONs and DFT calculations indicated that intramolecular coordination by the oxygen of the methoxy-propyl pendant groups may take place. The nanoscopic dimensions of the MONs were further tuned by varying the exfoliation conditions and through "liquid cascade centrifugation". Aqueous suspensions of the nanosheets were used as sensors to detect aromatic heterocycles with clear differences in binding behaviour observed and quantified.

9.
BMC Public Health ; 18(1): 932, 2018 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-30055592

RESUMO

BACKGROUND: In 2016 an estimated 1.9 billion adults world-wide were either overweight or obese. The health consequences of obesity are responsible for 2.8 million preventable deaths per year. The WHO now considers obesity as a global epidemic and recommends population-wide health promotion strategies to address this issue. Weight gain is caused by increased energy intake and physical inactivity, so treatment should focus on changes to behaviour regarding diet and physical activity. DISCUSSION: The WHO has also recognised the importance of social resources as a valuable agent for behaviour change in health promotion. Social resources are translated at the community level as support provided by significant others such as family, partners and peers, in the form of information, material aid and encouragement. Social support has been shown to improve health and well-being, whereas social isolation has been shown to have a negative impact on health outcomes. Social support provided by peers has been shown to be a useful strategy to employ in weight management programmes. The documented increased use of ICT and social media has presented health promoters with a potentially useful medium to increase social support for weight management. CONCLUSION: While the use of social media for health promotion is an emerging field of investigation, preliminary research suggests that it increases participant engagement, and may provide a cost-effective tool to provide social support for individuals participating in weight management programmes. With stringent privacy protocols in place, social media may be a useful, cost-effective accompaniment to multifactorial weight management programmes. However more research is needed to identify how to make the best use of social media as health promotion tool.


Assuntos
Promoção da Saúde/métodos , Obesidade/terapia , Sobrepeso/terapia , Mídias Sociais , Programas de Redução de Peso/métodos , Adulto , Peso Corporal , Análise Custo-Benefício , Feminino , Promoção da Saúde/economia , Humanos , Masculino , Obesidade/epidemiologia , Sobrepeso/epidemiologia , Privacidade , Mídias Sociais/economia , Apoio Social , Programas de Redução de Peso/economia
10.
J Aging Phys Act ; 26(4): 553-560, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29283746

RESUMO

We explored perceptions of social dance as a possible intervention to improve cognitive function in older adults with subjective memory complaints. A total of 30 participants (19 females; mean age = 72.6 years; SD = 8.2) took part in the study. This included 21 participants who had self-reported subjective memory complaints and nine spouses who noticed spousal memory loss. Semistructured interviews were conducted, and a thematic analysis was used to analyze the data. Three main themes were constructed: (a) dance seen as a means of promoting social interaction; (b) chronic illness as a barrier and facilitator to participation; and (c) social dance representing nostalgic connections to the past. Overall, the participants were positive about the potential attractiveness of social dance to improve cognitive and social functioning and other aspects of health. In future research, it is important to examine the feasibility of a social dance intervention among older adults with subjective memory complaints.


Assuntos
Cognição , Dançaterapia , Transtornos da Memória/terapia , Idoso , Idoso de 80 Anos ou mais , Dança/psicologia , Feminino , Humanos , Relações Interpessoais , Masculino , Autorrelato
11.
Int Orthop ; 42(4): 805-810, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28868567

RESUMO

INTRODUCTION: Newer TKR designs have been introduced to the market with the aim of overcoming common sizing problems with older TKR designs. Furthermore, since a sizable percentage of patients with OA present with disease limited to the medial/lateral knee compartment in addition to the patellofemoral joint, for whom, a customized bi-compartmental knee replacement (BKR) is available as a treatment option. To date, there is very little information regarding knee strength and mechanics during gait for patients implanted with these modern TKR and BKR designs. The purpose of the study was to evaluate knee strength and mechanics during walking for patients with either a modern off the shelf TKR or a customized BKR and compare these findings to a cohort of healthy controls. METHODS: Twelve healthy controls, eight BKR, and nine TKR patients participated in the study. Maximal isometric knee strength was evaluated. 3D kinematic and kinetic analyses were conducted for level walking. RESULTS: The TKR knee exhibited less peak extensor torque when compared to, both the BKR and control limbs (p < 0.05). The TKR knee had less extensor moment at stance than both the BKR and control knees (p < 0.05). Both the BKR and control knees displayed larger internal rotation at stance than that of the TKR knee (p < 0.05). DISCUSSION AND CONCLUSION: This study suggests that, for patients that exhibit isolated OA of the tibiofemoral joint, using a customized BKR implant is a viable treatment option and may contribute to superior mechanical advantages.


Assuntos
Artroplastia do Joelho/métodos , Análise da Marcha/métodos , Osteoartrite do Joelho/cirurgia , Idoso , Fenômenos Biomecânicos , Feminino , Marcha/fisiologia , Humanos , Articulação do Joelho/fisiopatologia , Articulação do Joelho/cirurgia , Prótese do Joelho/efeitos adversos , Masculino , Pessoa de Meia-Idade , Amplitude de Movimento Articular/fisiologia , Caminhada/fisiologia
12.
Int J Neurosci ; 127(3): 243-252, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27113638

RESUMO

Purpose/Aim of the study: Poor cardiovascular health, including obesity and altered lipid profiles at mid-life, are linked to increased risk of Alzheimer's disease (AD). The biological mechanisms linking cardiovascular health and cognitive function are unclear though are likely to be multifactorial. This study examined the association between various lipoproteins and cognitive functioning in ageing women. MATERIALS AND METHODS: We investigated the relationship between readily available biomarkers (i.e. serum lipoprotein) and cognitive decline in domains associated with increased risk of AD (e.g. episodic verbal memory performance and subjective memory complaint). We report cross-sectional data investigating the relationship between serum total cholesterol, triglycerides, high-density lipoprotein (HDL-C) and low-density lipoprotein with verbal memory and learning ability in 130 women with and without memory complaints (n = 71 and 59, respectively) drawn from a study investigating cognitively healthy Western Australians (average age 62.5 years old). RESULTS: After statistical modelling that controlled for the effects of age, depression and apolipoprotein E genotype, HDL-C was significantly associated with better verbal learning and memory performance, specifically short and long delay-free recalls (F = 3.062; p < .05 and F = 3.2670; p < .05, respectively). CONCLUSION: Our cross-sectional findings suggest that the positive effect of HDL-C on verbal memory may be present much earlier than previously reported and provide further support for the role of HDL-C in healthy brain ageing. Further exploration of the protective effect of HDL-C on cognitive function in ageing is warranted through follow-up, longitudinal studies.


Assuntos
Envelhecimento/sangue , Cognição/fisiologia , Envelhecimento Cognitivo , Lipoproteínas HDL/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Apolipoproteínas E/genética , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Memória/fisiologia , Pessoa de Meia-Idade , Testes Neuropsicológicos , Análise de Regressão , Aprendizagem Verbal
13.
Plant Cell ; 25(10): 4014-27, 2013 10.
Artigo em Inglês | MEDLINE | ID: mdl-24179128

RESUMO

The assembly of respiratory complexes is a multistep process, requiring coordinate expression of mitochondrial and nuclear genes and cofactor biosynthesis. We functionally characterized the iron-sulfur protein required for NADH dehydrogenase (INDH) in the model plant Arabidopsis thaliana. An indh knockout mutant lacked complex I but had low levels of a 650-kD assembly intermediate, similar to mutations in the homologous NUBPL (nucleotide binding protein-like) in Homo sapiens. However, heterozygous indh/+ mutants displayed unusual phenotypes during gametogenesis and resembled mutants in mitochondrial translation more than mutants in complex I. Gradually increased expression of INDH in indh knockout plants revealed a significant delay in reassembly of complex I, suggesting an indirect role for INDH in the assembly process. Depletion of INDH protein was associated with decreased (35)S-Met labeling of translation products in isolated mitochondria, whereas the steady state levels of several mitochondrial transcripts were increased. Mitochondrially encoded proteins were differentially affected, with near normal levels of cytochrome c oxidase subunit2 and Nad7 but little Nad6 protein in the indh mutant. These data suggest that INDH has a primary role in mitochondrial translation that underlies its role in complex I assembly.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Complexo I de Transporte de Elétrons/metabolismo , Proteínas Ferro-Enxofre/metabolismo , Mitocôndrias/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas Ferro-Enxofre/genética , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Biossíntese de Proteínas , Multimerização Proteica
14.
Eur J Nutr ; 55(4): 1503-13, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26130325

RESUMO

BACKGROUND: There is increasing evidence supporting an association of higher serum vitamin D concentration with better cognitive performance in older individuals. However, to date, consideration of the putative association between vitamin D and cognition has been based principally on studies investigating clinical participant samples manifesting vitamin D deficiency, particularly in older people. Moreover, relationships between vitamin D and cognition are typically not considered in the context of counter-regulatory calcium-modulating hormones or calcium homeostasis. OBJECTIVE: Serum vitamin D/bioactive (ionised) calcium/parathyroid hormone homeostasis was considered in the context of cognitive performance in healthy, middle-aged and older individuals. DESIGN: A cross-sectional sample of 179 participants between the ages of 47-84 years was recruited for this study (114 females, 65 males). Participants provided fasting blood samples for analysis of serum 25-hydroxyvitamin D levels, ionised calcium (iCa) and parathyroid hormone (PTH) and completed cognitive measures of verbal episodic learning and memory. RESULTS: Serum 25-hydroxyvitamin D concentrations were negatively associated (with and without covariates of age, gender, depression and NART scores, iCa, and PTH) with measures of verbal episodic learning and memory, in particular with trial 5 of the Rey Auditory Verbal Learning Test (RAVLT) and long-delay free recall on the RAVLT. CONCLUSION: Overall, the findings from this study suggest an association between higher vitamin D status and poorer performance on verbal episodic memory in middle-aged and older individuals with normal vitamin D-calcium-PTH homeostasis. Despite requiring replication in other participant samples, this is a potentially important finding as it indicates that it may not be beneficial from a cognitive perspective to provide vitamin D supplements in individuals with already adequate vitamin D status.


Assuntos
Memória Episódica , Vitamina D/análogos & derivados , Idoso , Idoso de 80 Anos ou mais , Cálcio/sangue , Cognição/efeitos dos fármacos , Estudos Transversais , Jejum , Feminino , Humanos , Aprendizagem/efeitos dos fármacos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue , Vitamina D/sangue , Deficiência de Vitamina D/sangue
15.
Acta Paediatr ; 105(5): e209-18, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26719022

RESUMO

AIM: The aim of this study was to investigate the associations between early diet and academic performance during childhood. METHODS: Participants were from the Western Australian Pregnancy Cohort (Raine) Study (n = 2287). Frequency of consumption of food and beverages was collected at the one-, two- and three-year follow-ups, using a 24-hour food recall. Diet scores were developed from the number of eating occasions. The Western Australian Literacy and Numeracy Assessment (WALNA) data from grades five (age 10) and seven (age 12) were linked to the Raine study using The Western Australian Data Linkage System. The association between diet scores and WALNA scores was assessed using multivariate linear regression models. RESULTS: A higher (i.e. better quality) diet score at one year of age was associated with significantly higher scores in mathematics, reading, writing and spelling at both grades five and seven. Associations were observed between a higher diet score at two years and academic scores for mathematics, writing and spelling at grade seven. Higher dairy consumption at ages one, two and three, and higher fruit consumption at age one were associated with higher academic scores at all ages. CONCLUSION: Quality of early diet may be a predictor for later academic achievement.


Assuntos
Logro , Fenômenos Fisiológicos da Nutrição Infantil , Cognição , Dieta Saudável/psicologia , Criança , Pré-Escolar , Inquéritos sobre Dietas , Feminino , Seguimentos , Humanos , Lactente , Modelos Lineares , Masculino , Análise Multivariada , Estudos Prospectivos , Austrália Ocidental
16.
J Am Chem Soc ; 137(30): 9722-9, 2015 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-26153733

RESUMO

Here we report a new class of hydrogels formed by polymers that are cross-linked through subcomponent self-assembled metal-organic cages. Selective encapsulation of guest molecules within the cages creates two distinct internal phases within the hydrogel, which allows for contrasting release profiles of related molecules depending on their aptitude for encapsulation within the cages. The hydrogels were fabricated into microparticles via a droplet-based microfluidic approach and proved responsive to a variety of stimuli, including acid and competing amine or aldehyde subcomponents, allowing for the triggered release of cargo.


Assuntos
Reagentes de Ligações Cruzadas/química , Compostos Ferrosos/química , Hidrogéis/química , Polietilenoglicóis/química , Ácidos/química , Aldeídos/química , Aminas/química , Hidrogéis/síntese química , Estrutura Molecular , Tamanho da Partícula , Propriedades de Superfície
17.
Nature ; 457(7225): 63-6, 2009 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-19122636

RESUMO

Self-gravity plays a decisive role in the final stages of star formation, where dense cores (size approximately 0.1 parsecs) inside molecular clouds collapse to form star-plus-disk systems. But self-gravity's role at earlier times (and on larger length scales, such as approximately 1 parsec) is unclear; some molecular cloud simulations that do not include self-gravity suggest that 'turbulent fragmentation' alone is sufficient to create a mass distribution of dense cores that resembles, and sets, the stellar initial mass function. Here we report a 'dendrogram' (hierarchical tree-diagram) analysis that reveals that self-gravity plays a significant role over the full range of possible scales traced by (13)CO observations in the L1448 molecular cloud, but not everywhere in the observed region. In particular, more than 90 per cent of the compact 'pre-stellar cores' traced by peaks of dust emission are projected on the sky within one of the dendrogram's self-gravitating 'leaves'. As these peaks mark the locations of already-forming stars, or of those probably about to form, a self-gravitating cocoon seems a critical condition for their existence. Turbulent fragmentation simulations without self-gravity-even of unmagnetized isothermal material-can yield mass and velocity power spectra very similar to what is observed in clouds like L1448. But a dendrogram of such a simulation shows that nearly all the gas in it (much more than in the observations) appears to be self-gravitating. A potentially significant role for gravity in 'non-self-gravitating' simulations suggests inconsistency in simulation assumptions and output, and that it is necessary to include self-gravity in any realistic simulation of the star-formation process on subparsec scales.


Assuntos
Gravitação , Astros Celestes/química , Algoritmos , Astronomia , Monóxido de Carbono/análise , Simulação por Computador
18.
BMC Public Health ; 15: 509, 2015 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-26012783

RESUMO

BACKGROUND: Over the last three decades, overweight and obesity and the associated health consequences have become global public health priorities. Methods that have been tried to address this problem have not had the desired impact, suggesting that other approaches need to be considered. One of the lessons learned throughout these attempts is that permanent weight loss requires sustained dietary and lifestyle changes, yet adherence to weight management programs has often been noted as one of the biggest challenges. This trial aims to address this issue by examining whether social media, as a potential health promotion tool, will improve adherence to a weight management program. To test the effectiveness of this measure, the designated program will be delivered via the popular social networking site Facebook, and compared to a standard delivery method that provides exactly the same content but which is communicated through a pamphlet. The trial will be conducted over a period of twelve weeks, with a twelve week follow-up. Although weight loss is expected, this study will specifically investigate the effectiveness of social media as a program delivery method. The program utilised will be one that has already been proven to achieve weight loss, namely The CSIRO Total Wellbeing Diet. METHODS/DESIGN: This project will be conducted as a 3-arm randomised controlled trial. One hundred and twenty participants will be recruited from the Perth community, and will be randomly assigned to one of the following three groups: the Facebook group, the pamphlet group, or a control group. The Facebook Group will receive the weight management program delivered via a closed group in Facebook, the Pamphlet Group will be given the same weight management program presented in a booklet, and the Control Group will follow the Australian Dietary Guidelines and the National Physical Activity Guidelines for Adults as usual care. Change in weight, body composition and waist circumference will be initial indicators of adherence to the program. Secondary outcome measures will be blood glucose, insulin, blood pressure, arterial stiffness, physical activity, eating behaviour, mental well-being (stress, anxiety, and depression), social support, self-control, self-efficacy, Facebook activity, and program evaluation. DISCUSSION: It is expected that this trial will support the use of social media - a source of social support and information sharing - as a delivery method for weight management programs, enhancing the reduction in weight expected from dietary and physical activity changes. Facebook is a popular, easy to access and cost-effective online platform that can be used to assist the formation of social groups, and could be translated into health promotion practice relatively easily. It is anticipated in the context of the predicted findings that social media will provide an invaluable resource for health professionals and patients alike. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Register (ANZCTR): ACTRN12614000536662. Date registered: 21 May 2014.


Assuntos
Comportamentos Relacionados com a Saúde , Promoção da Saúde/métodos , Saúde Mental , Sobrepeso/terapia , Mídias Sociais , Adulto , Idoso , Ansiedade/epidemiologia , Austrália , Pesos e Medidas Corporais , Análise Custo-Benefício , Depressão/epidemiologia , Dieta , Feminino , Humanos , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Motivação , Obesidade/epidemiologia , Obesidade/terapia , Sobrepeso/epidemiologia , Avaliação de Programas e Projetos de Saúde , Projetos de Pesquisa , Autoeficácia
19.
Chemistry ; 20(1): 279-91, 2014 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-24302604

RESUMO

Blending different low molecular weight gelators (LMWGs) provides a convenient route to tune the properties of a gel and incorporate functionalities such as fluorescence. Blending a series of gelators having a common bis-urea motif, and functionalised with different amino acid-derived end-groups and differing length alkylene spacers is reported. Fluorescent gelators incorporating 1- and 2-pyrenyl moieties provide a probe of the mixed systems alongside structural and morphological data from powder diffraction and electron microscopy. Characterisation of the individual gelators reveals that although the expected α-urea tape motif is preserved, there is considerable variation in the gelation properties, molecular packing, fibre morphology and rheological behaviour. Mixing of the gelators revealed examples in which: 1) the gels formed separate, orthogonal networks maintaining their own packing and morphology, 2) the gels blended together into a single network, either adopting the packing and morphology of one gelator, or 3) a new structure not seen for either of the gelators individually was created. The strong binding of the urea functionalities to anions was exploited as a means of breaking down the gel structure, and the use of fluorescent gel blends provides new insights into anion-mediated gel dissolution.

20.
J Child Psychol Psychiatry ; 55(9): 1017-24, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24673485

RESUMO

BACKGROUND: The aim of the study was to investigate prospective associations between dietary patterns and cognitive performance during adolescence. METHODS: Participants were sourced from the Western Australian Pregnancy Cohort (Raine) Study that includes 2868 children born between 1989 and 1992 in Perth, Western Australia. When the children were 17 years old (2006-2009), cognitive performance was assessed using a computerized cognitive battery of tests (CogState) that included six tasks. Using a food frequency questionnaire administered when the children were 14 years old (2003-2006), 'Healthy' and 'Western' dietary patterns were identified by factor analysis. Associations between dietary patterns at 14 years of age and cognitive performance at 17 years of age were assessed prospectively using multivariate regression models. RESULTS: Dietary and cognitive performance data were available for 602 participants. Following adjustment for the 'Healthy' dietary pattern, total energy intake, maternal education, family income, father's presence in the family, family functioning and gender, we found that a longer reaction time in the detection task (ß = .016; 95% CI: 0.004; 0.028; p = .009) and a higher number of total errors in the Groton Maze Learning Test - delayed recall task (ß = .060; 95% CI: 0.006; 0.114; p = .029) were significantly associated with higher scores on the 'Western' dietary pattern. The 'Western' dietary pattern was characterized by high intakes of take-away food, red and processed meat, soft drink, fried and refined food. We also found that within the dietary patterns, high intake of fried potato, crisps and red meat had negative associations, while increased fruit and leafy green vegetable intake had positive associations with some aspects of cognitive performance. CONCLUSION: Higher dietary intake of the 'Western' dietary pattern at age 14 is associated with diminished cognitive performance 3 years later, at 17 years.


Assuntos
Cognição/fisiologia , Dieta/estatística & dados numéricos , Desempenho Psicomotor/fisiologia , Adolescente , Feminino , Humanos , Masculino , Estudos Prospectivos , Austrália Ocidental/epidemiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA