290 research outputs found

    Dehydration entropy drives liquid-liquid phase separation by molecular crowding

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    Liquid-liquid phase separation occurs in cells and can be induced in artificial systems, but the mechanism of the effect of molecular crowders is unclear. Here dehydration entropy-driven phase separation of model charged polymers lacking any chemical complexity or hydrophobicity is shown to be enhanced by polyethylene glycol. Complex coacervation driven liquid-liquid phase separation (LLPS) of biopolymers has been attracting attention as a novel phase in living cells. Studies of LLPS in this context are typically of proteins harboring chemical and structural complexity, leaving unclear which properties are fundamental to complex coacervation versus protein-specific. This study focuses on the role of polyethylene glycol (PEG)-a widely used molecular crowder-in LLPS. Significantly, entropy-driven LLPS is recapitulated with charged polymers lacking hydrophobicity and sequence complexity, and its propensity dramatically enhanced by PEG. Experimental and field-theoretic simulation results are consistent with PEG driving LLPS by dehydration of polymers, and show that PEG exerts its effect without partitioning into the dense coacervate phase. It is then up to biology to impose additional variations of functional significance to the LLPS of biological systems.11Ysciescopu

    Review of economic bubbles

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    © 2016 Elsevier Ltd. All rights reserved. This paper investigates the history of economic bubbles and attempts to identify whether there are direct correlations between different bubbles. To support this research, literature has been consulted on historical and recent bubbles, theories surrounding speculation, the market for venture capital, and bubbles in the technology sector. By analysing a range of bubbles, rather than just those in the technology sector, general bubble-principles are also identified. All the economic bubbles are classified under "uncontrolled risk" and a recommended method that can detect and analyse full impacts by uncontrolled risk will be presented, together with future directions to be discussed

    DNA looping provides stability and robustness to the bacteriophage lambda switch

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    The bistable gene regulatory switch controlling the transition from lysogeny to lysis in bacteriophage lambda presents a unique challenge to quantitative modeling. Despite extensive characterization of this regulatory network, the origin of the extreme stability of the lysogenic state remains unclear. We have constructed a stochastic model for this switch. Using Forward Flux Sampling simulations, we show that this model predicts an extremely low rate of spontaneous prophage induction in a recA mutant, in agreement with experimental observations. In our model, the DNA loop formed by octamerization of CI bound to the O_L and O_R operator regions is crucial for stability, allowing the lysogenic state to remain stable even when a large fraction of the total CI is depleted by nonspecific binding to genomic DNA. DNA looping also ensures that the switch is robust to mutations in the order of the O_R binding sites. Our results suggest that DNA looping can provide a mechanism to maintain a stable lysogenic state in the face of a range of challenges including noisy gene expression, nonspecific DNA binding and operator site mutations.Comment: In press on PNAS. Single file contains supplementary inf

    Non-pharmacological interventions for adults with intellectual disabilities and depression

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    Background: Although high rates of depression symptoms are reported in adults with intellectual disabilities (IDs), there is a lack of knowledge about non-pharmacological treatment options for depression in this population. The first research question of this paper is: Which non-pharmacological interventions have been studied in adults with ID and depression? The second research question is: What were the results of these non-pharmacological interventions?. Method: Systematic review of the literature with an electronic search in six databases has been completed with hand searches. Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines have been followed. Selected studies met predefined inclusion criteria. Results: Literature search resulted in 4267 papers of which 15 met the inclusion criteria. Five different types of non-pharmacological interventions have been studied: cognitive behavioural therapy, behavioural therapy, exercise intervention, social problem-solving skills programme and bright light therapy. Conclusion: There are only a few studies of good quality evaluating non-pharmacological interventions for adults with ID and depression. Some of these studies, especially studies on cognitive behavioural therapy, show good results in decreasing depressive symptoms. High-quality randomised controlled trials evaluating non-pharmacological

    Handgrip strength and health outcomes: Umbrella review of systematic reviews with meta-analyses of observational studies

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    Purpose: The aim of the present study was to assess both the credibility and strength of evidence arising from systematic reviews with meta-analyses of observational studies on handgrip strength and health outcomes. Methods: An umbrella review of systematic reviews with meta-analyses of observational studies was conducted. We assessed meta-analyses of observational studies based on random-effect summary effect sizes and their p values, 95% prediction intervals, heterogeneity, small-study effects, and excess significance. We graded the evidence from convincing (Class I) to weak (Class IV). Results: From 504 articles returned in a search of the literature, 8 systematic reviews were included in our review, with a total of 11 outcomes. Overall, 9 of the 11 of the outcomes reported nominally significant summary results (p < 0.05), with 4 associations surviving the application of the more stringent p value (p < 10−6). No outcome presented convincing evidence. Three associations showed Class II evidence (i.e., highly suggestive): (1) higher handgrip values at baseline were associated with a minor reduction in mortality risk in the general population (n = 34 studies; sample size = 1,855,817; relative risk = 0.72; 95% confidence interval: 0.67–0.78), (2) cardiovascular death risk in mixed populations (n = 15 studies; relative risk = 0.84; 95% confidence interval: 0.78–0.91), and (3) incidence of disability (n = 7 studies; relative risk = 0.76; 95% confidence interval: 0.66–0.87). Conclusion: The present results show that handgrip strength is a useful indicator for general health status and specifically for early all-cause and cardiovascular mortality, as well as disability. To further inform intervention strategies, future research is now required to fully understand mechanisms linking handgrip strength scores to these health outcomes

    Interventions for preventing oral mucositis for patients with cancer receiving treatment

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    Interventions for preventing oral mucositis for patients with cancer receiving treatmentTreatment for cancer (including bone marrow transplant) can cause oral mucositis (severe ulcers in the mouth). This painful condition can cause difficulties in eating, drinking and swallowing, and may also be associated with infections which may require the patient to stay longer in hospital. Different strategies are used to try and prevent this condition, and the review of trials found that some of these are effective. Two interventions, cryotherapy (ice chips) and keratinocyte growth factor (palifermin®) showed some benefit in preventing mucositis. Sucralfate is effective in reducing the severity of mucositis, and a further seven interventions, aloe vera, amifostine, intravenous glutamine, granulocyte‐colony stimulating factor (G‐CSF), honey, laser and antibiotic lozenges containing polymixin/tobramycin/amphotericin (PTA) showed weaker evidence of benefit. These were evaluated in patients with different types of cancer, undergoing different types of cancer treatment. Benefits may be restricted to the disease and treatment combinations evaluated

    The effects of computer-based games and collaboration in large groups vs. collaboration in pairs or traditional methods

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    As new technologies have emerged in the last few years, the learning process has been changing. New and powerful e-learning systems are being developed and new teaching methods can be used in classrooms. In this paper, we present a computer-based game with an educational background that is played on a large-size tabletop display. The game can be used as reinforcement for educational content related to historical ages. The game uses natural interaction. A study to compare the traditional learning method with a collaborative learning method using the game was carried out. A group of up to 12 children could learn together using the game. The experience of children in large groups was also compared with the experience of children playing in pairs. One hundred children between 8 and 11 years old participated in the study; they were divided into three groups (LGroup, Pairs, TClass). When the pretest and the post-test results were compared, it was shown that the children learned the contents in all three groups. The results also showed that there were statistically significant differences between the traditional method and the game played in a large group in favour of children who played the game in the large group. The knowledge acquired was independent from gender and age. There were no statistically significant differences between learning in large groups or learning in pairs. In both cases, the children expressed their satisfaction for the game and found it easy to use. Therefore, playing games of this type collaboratively in large groups or in pairs can be a valuable learning method that can be combined with traditional methods.This work was funded by the Spanish Government (MICINN) in the APRENDRA project (TIN2009-14319-C02-01). We would like to thank the following for their contributions: - The "Escola d'Estiu" (UPV) and especially Juan Cano, Miguelon Gimenez, and Javier Irimia. - The Engeba school of Valencia (Spain). - Encama Torres, Juan Martinez, Sonia, and M. Jose Vicent for their help. - The children's parents who signed the agreement to allow their children to participate in the study. - The children who participated in the study. - The ETSInf for letting us use its facilities during the testing phase. - The reviewers for their valuable comments.Martín San José, JF.; Juan Lizandra, MC.; Segui, I.; García García, I. (2015). The effects of computer-based games and collaboration in large groups vs. collaboration in pairs or traditional methods. Computers and Education. 87:42-54. https://doi.org/10.1016/j.compedu.2015.03.018S42548
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