244 research outputs found
Using Group Model Building to Understand Factors That Influence Childhood Obesity in an Urban Environment
Background: Despite increased attention, conventional views of obesity are based upon individual behaviors, and children and parents living with obesity are assumed to be the primary problem solvers. Instead of focusing exclusively on individual reduction behaviors for childhood obesity, greater focus should be placed on better understanding existing community systems and their effects on obesity. The Milwaukee Childhood Obesity Prevention Project is a community-based coalition established to develop policy and environmental change strategies to impact childhood obesity in Milwaukee, Wisconsin. The coalition conducted a Group Model Building exercise to better understand root causes of childhood obesity in its community. Methods: Group Model Building is a process by which a group systematically engages in model construction to better understand the systems that are in place. It helps participants make their mental models explicit through a careful and consistent process to test assumptions. This process has 3 main components: (1) assembling a team of participants; (2) conducting a behavior-over-time graphs exercise; and (3) drawing the causal loop diagram exercise. Results: The behavior-over-time graph portion produced 61 graphs in 10 categories. The causal loop diagram yielded 5 major themes and 7 subthemes. Conclusions: Factors that influence childhood obesity are varied, and it is important to recognize that no single solution exists. The perspectives from this exercise provided a means to create a process for dialogue and commitment by stakeholders and partnerships to build capacity for change within the community
Impact of environmental conditions on the concentrations of trichothecenes, their glucosides, and emerging fusarium toxins in naturally contaminated, irradiated, and fusarium iangsethiae inoculated oats
Trichothecenes produced by Fusarium species are commonly detected in oats. However, the ratios of the concentrations of free trichothecenes and their conjugates and how they are impacted by different interacting environmental conditions are not well documented. This study aims to examine the effect of water activity (0.95 and 0.98 aw) and temperature (20 and 25 Β°C) stress on the production of T-2 and HT-2 toxins, deoxynivalenol and their conjugates, as well as diacetoxyscirpenol (DAS). Multiple mycotoxins were detected using liquid chromatographyβtandem mass spectrometry from 64 contaminated oat samples. The highest concentrations of HT-2-glucoside (HT-2-Glc) were observed at 0.98 aw and 20 Β°C, and were higher than other type A trichothecenes in the natural oatsβ treatments. However, no statistical differences were found between the mean concentrations of HT-2-Glc and HT-2 toxins in all storage conditions analysed. DAS concentrations were generally low and highest at 0.95 aw and 20 Β°C, while deoxynivalenol-3-glucoside levels were highest at 0.98 aw and 20 Β°C in the naturally contaminated oats. Emerging mycotoxins such as beauvericin, moniliformin, and enniatins mostly increased with a rise in water activity and temperature in the naturally contaminated oats treatment. This study reinforces the importance of storage aw and temperature conditions in the high risk of free and modified toxin contamination of small cereal grains
Atorvastatin-Loaded Dissolving Microarray Patches for Long-Acting Microdepot Delivery: Comparison of Nanoparticle and Microparticle Drug Formulations
The increasing popularity of prolonged-release dosage forms, owing to their ability to provide continuous drug release after administration, has significantly improved patient compliance and overall quality of life. However, achieving prolonged release beyond 24 h frequently requires the use of invasive methods, including injections or implants, which may prove challenging for people suffering from needle phobia. This study introduces atorvastatin (ATR) microparticles (MPs) or nanocrystal (NCs) dissolving microarray patches (D-MAPs) as a noninvasive alternative for intradermal drug delivery over a two-week period for the management of hyperlipidemia. The MP-loaded D-MAPs exhibited an average drug loading of 5.15 Β± 0.4 mg of ATR per patch, surpassing the 2.4 Β± 0.11 mg/patch observed with NC-loaded D-MAPs. Skin deposition studies demonstrated the superior performance of MP D-MAPs, which delivered 2.0 Β± 0.33 mg of ATR per 0.75 cm2 patch within 24 h, representing 38.76% of the initial amount of drug loaded. In contrast, NC D-MAPs delivered approximately 0.89 Β± 0.12 mg of ATR per 0.75 cm2 patch at 24 h, equivalent to 38.42 Β± 5.13% of the initial ATR loaded. Due to their favorable results, MP D-MAPs were chosen for an in vivo study using SpragueβDawley rats. The findings demonstrated the capacity of D-MAPs to deliver and attain therapeutically relevant ATR concentrations (>20 ng/mL) for 14 days after a single 24-h application. This study is the first to successfully demonstrate the long-acting transdermal delivery of ATR using MP-loaded D-MAPs after a 24-h single-dose application. The innovative D-MAP system, particularly when loaded with MP, arises as a promising, minimally invasive, long-acting substitute for ATR delivery. This technology has the potential to improve patient compliance and therapeutic outcomes while also significantly advancing the field of transdermal drug delivery
Dissolving microarray patches for transdermal delivery of risperidone for schizophrenia management
Schizophrenia is a psychiatric disorder that results from abnormal levels of neurotransmitters in the brain. Risperidone (RIS) is a common drug prescribed for the treatment of schizophrenia. RIS is a hydrophobic drug that is typically administered orally or intramuscularly. Transdermal drug delivery (TDD) could potentially improve the delivery of RIS. This study focused on the development of RIS nanocrystals (NCs), for the first time, which were incorporated into dissolving microneedle array patches (DMAPs) to facilitate the drug delivery of RIS. RIS NCs were formulated via wet-media milling technique using poly(vinylalcohol) (PVA) as a stabiliser. NCs with particle size of 300 nm were produced and showed an enhanced release profile up to 80 % over 28 days. Ex vivo results showed that 1.16 Β± 0.04 mg of RIS was delivered to both the receiver compartment and full-thickness skin from NCs loaded DMAPs compared to 0.75 Β± 0.07 mg from bulk RIS DMAPs. In an in vivo study conducted using female Sprague Dawley rats, both RIS and its active metabolite 9-hydroxyrisperidone (9-OH-RIS) were detected in plasma samples for 5 days. In comparison with the oral group, DMAPs improved the overall pharmacokinetic profile in plasma with a βΌ 15 folds higher area under the curve (AUC) value. This work has represented the novel delivery of the antipsychotic drug, RIS, through microneedles. It also offers substantial evidence to support the broader application of MAPs for the transdermal delivery of poorly water-soluble drugs
Uma metodologia de avaliação de desempenho de sistemas Peer-To-Peer baseados em tabelas Hash DistribuΓdas
Resumo: As tabelas hash distribuΓdas (DHTs, distributed hash tables) sΓ£o redes par-a-par (P2P, peer-to-peer) estruturadas que permitem a inserção de dados indexados por chaves. Elas sΓ£o compostas por um conjunto de participantes (nodos ou pares) dinΓ’micos sem o controle de uma autoridade central. As DHTs tornaram-se populares ao longo da ΓΊltima dΓ©cada e hoje possuem diversas aplicaçáes, algumas contendo milhΓ΅es de nodos espalhados ao redor do planeta. Existe uma grande quantidade de DHTs, as quais podem possuir vΓ‘rias implementaçáes e serem configuradas atravΓ©s de diversos parΓ’metros. Entretanto, nΓ£o hΓ‘ um consenso sobre a melhor maneira de avaliar o desempenho de uma DHT, o que dificulta a comparação entre o grande nΓΊmero de DHTs existentes e, consequentemente, a escolha da DHT ideal para cada sistema. Esta dissertação apresenta uma revisΓ£o de trabalhos que propΓ΅em metodologias de avaliação de desempenho de DHTs e de trabalhos que simplesmente avaliam desempenho de DHTs, sem propor metodologias. Com base nesta revisΓ£o uma nova metodologia de avaliação de desempenho de DHTs Γ© proposta. Esta metodologia define um conjunto de testes de desempenho composto por mΓ©tricas e cargas de trabalho. Estas mΓ©tricas e cargas de trabalho sΓ£o baseadas nos pontos em comum encontrados nos diversos trabalhos estudados. A metodologia apresentada define tambΓ©m um modelo para a execução de avaliaçáes de desempenho de DHTs composto por trΓͺs entidades: mestre, controlador e nodo. Este trabalho apresenta tambΓ©m a ferramenta Dhtperf, que alΓ©m de implementar a metodologia proposta permite facilmente a definição de novas mΓ©tricas e cargas de trabalho. Esta ferramenta foi utilizada para realizar avalia- çáes de desempenho de diversas DHTs existentes em dois ambientes distintos, validando a metodologia proposta. Os resultados obtidos nas avaliaçáes realizadas sΓ£o apresentados e discutidos
Behaviour and Physiology: The Thermal Strategy of Leatherback Turtles
Background: Adult leatherback turtles (Dermochelys coriacea) exhibit thermal gradients between their bodies and the environment of $8uC in sub-polar waters and #4uC in the tropics. There has been no direct evidence for thermoregulation in leatherbacks although modelling and morphological studies have given an indication of how thermoregulation may be achieved. Methodology/Principal Findings: We show for the first time that leatherbacks are indeed capable of thermoregulation from studies on juvenile leatherbacks of 16 and 37 kg. In cold water (, 25uC), flipper stroke frequency increased, heat loss through the plastron, carapace and flippers was minimized, and a positive thermal gradient of up to 2.3uC was maintained between body and environment. In warm water (25 β 31uC), turtles were inactive and heat loss through their plastron, carapace and flippers increased. The thermal gradient was minimized (0.5uC). Using a scaling model, we estimate that a 300 kg adult leatherback is able to maintain a maximum thermal gradient of 18.2uC in cold sub-polar waters. Conclusions/Significance: In juvenile leatherbacks, heat gain is controlled behaviourally by increasing activity while heat flux is regulated physiologically, presumably by regulation of blood flow distribution. Hence, harnessing physiology and behaviour allows leatherbacks to keep warm while foraging in cold sub-polar waters and to prevent overheating in
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Establishing Zebrafish as a Novel Exercise Model: Swimming Economy, Swimming-Enhanced Growth and Muscle Growth Marker Gene Expression
Zebrafish has been largely accepted as a vertebrate multidisciplinary model but its usefulness as a model for exercise physiology has been hampered by the scarce knowledge on its swimming economy, optimal swimming speeds and cost of transport. Therefore, we have performed individual and group-wise swimming experiments to quantify swimming economy and to demonstrate the exercise effects on growth in adult zebrafish
The Complete Genome Sequence of the Pathogenic Intestinal Spirochete Brachyspira pilosicoli and Comparison with Other Brachyspira Genomes
Background: The anaerobic spirochete Brachyspira pilosicoli colonizes the large intestine of various species of birds and mammals, including humans. It causes ''intestinal spirochetosis'', a condition characterized by mild colitis, diarrhea and reduced growth. This study aimed to sequence and analyse the bacterial genome to investigate the genetic basis of its specialized ecology and virulence. Methodology/Principal Findings: The genome of B. pilosicoli 95/1000 was sequenced, assembled and compared with that of the pathogenic Brachyspira hyodysenteriae and a near-complete sequence of Brachyspira murdochii. The B. pilosicoli genome was circular, composed of 2,586,443 bp with a 27.9 mol% G+C content, and encoded 2,338 genes. The three Brachyspira species shared 1,087 genes and showed evidence of extensive genome rearrangements. Despite minor differences in predicted protein functional groups, the species had many similar features including core metabolic pathways. Genes distinguishing B. pilosicoli from B. hyodysenteriae included those for a previously undescribed bacteriophage that may be useful for genetic manipulation, for a glycine reductase complex allowing use of glycine whilst protecting from oxidative stress, and for aconitase and related enzymes in the incomplete TCA cycle, allowing glutamate synthesis and function of the cycle during oxidative stress. B. pilosicoli had substantially fewer methyl-accepting chemotaxis genes than B. hyodysenteriae and hence these species are likely to have different chemotactic responses that may help to explain their different host range and colonization sites. B. pilosicoli lacked the gene for a new putative hemolysin identified in B. hyodysenteriae WA1. Both B. pilosicoli and B. murdochii lacked the rfbBADC gene cluster found on the B. hyodysenteriae plasmid, and hence were predicted to have different lipooligosaccharide structures. Overall, B. pilosicoli 95/1000 had a variety of genes potentially contributing to virulence. Conclusions/Significance: The availability of the complete genome sequence of B. pilosicoli 95/1000 will facilitate functional genomics studies aimed at elucidating host-pathogen interactions and virulence
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