240 research outputs found

    Coarse-grained model of entropic allostery

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    Many signaling functions in molecular biology require proteins to bind to substrates such as DNA in response to environmental signals such as the simultaneous binding to a small molecule. Examples are repressor proteins which may transmit information via a conformational change in response to the ligand binding. An alternative entropic mechanism of "allostery" suggests that the inducer ligand changes the intramolecular vibrational entropy, not just the mean static structure. We present a quantitative, coarse-grained model of entropic allostery, which suggests design rules for internal cohesive potentials in proteins employing this effect. It also addresses the issue of how the signal information to bind or unbind is transmitted through the protein. The model may be applicable to a wide range of repressors and also to signaling in trans-membrane proteins

    Selective lability of ruthenium(II) arene amino acid complexes.

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    A series of organometallic complexes of the form [(PhH)Ru(amino acid)](+) have been synthesized using amino acids able to act as tridentate ligands. The straightforward syntheses gave enantiomerically pure complexes with two stereogenic centers due to the enantiopurity of the chelating ligands. Complexes were characterized in the solid-state and/or solution-state where the stability of the complex allowed. The propensity toward labilization of the coordinatively saturated complexes was investigated. The links between complex stability and structural features are very subtle. Nonetheless, H/D exchange rates of coordinated amino groups reveal more significant differences in reactivity linked to metallocycle ring size resulting in decreasing stability of the metallocycle as the amino acid side-chain length increases. The behavior of these systems in acid is unusual, apparently labilizing the carboxylate residue of the amino acid. This acid-catalyzed hemilability in an organometallic is relevant to the use of Ru(II) arenes in medicinal contexts due to the relatively low pH of cancerous cells.TGS and MO thank the EPSRC for Studentships EP/P505445/1 and EP/K503/009/1, respectively.This is the final version of the article. It was first published by ACS at http://pubs.acs.org/doi/abs/10.1021/ic502051

    Prospectus, October 10, 1984

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    SO YOU AND THE BULLY ON THE BLOCK ARE GOING TO DESTROY THE WORLD?\u27; PC Digest; Use your vote to make needed changes; First semester headaches; Auntie Miranda-Yes? or No?; Dear Reader; PC Happenings; Lifelong Learners to meet; Parkalnd schedules special registration; Workshop focuses on time management; Animal Health Technicians conference set; Health issues series continues; Emotional problems reason for help, not condemnation; Consumer Health Care Hotline; Notes of interest Prospectus read far and wide; Pictures worth more than a thousand words and dollars; Parkland instructor to teach GM class; Staff profile-Jim Scott-Entertainment writer; Advice from the duodenum-by Auntie Miranda; Wallace and Gray assets to both Parkland and \u27Taken in Marriage\u27; Music Poll; Explore the workings of the brain; Who\u27s top in pop?; Chick\u27s newest more than child\u27s play; Don\u27t miss a night of hilarity; Creative Corner...Especially for you!!; \u27The Foreigner\u27; The alarm clock-Monday morning blues; Natural selection; Bittersweet Memory; Pathways; Beautiful Stranger; Too Late; Love in the winter woods; \u27Doom Story\u27 the nightmare begins; Eternity; Green Eyes; Our day; Rejoice the Poet; Life Choices; Our place; Classifieds; Trust and acceptance provide supportive atmosphere; Change brings creation of destiny; Did You Know...; Kirby leads Cobra harriers to 7th; Lady Cobras win three, improve record to 18-5; A Tale of Three Freshmen; IM Volleyball; IM Football; Kirby says \u27Running is good for heart\u27; Schriefer takes pride in Parkland X-Country; Stewart places 3rd to lead Lady Cobras; Mullen twins guests on Cobra Raphttps://spark.parkland.edu/prospectus_1984/1009/thumbnail.jp

    The effectiveness of the Inspiring Futures parenting programme in improving behavioural and emotional outcomes in primary school children with behavioural or emotional difficulties: study protocol for a randomised controlled trial.

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    textabstractBackground: There is a need to build the evidence base of early interventions promoting children's health and development in the UK. Malachi Specialist Family Support Services ('Malachi') is a voluntary sector organisation based in the UK that delivers a therapeutic parenting group programme called Inspiring Futures to parents of children identified as having behavioural and emotional difficulties. The programme comprises two parts, delivered sequentially: (1) a group-based programme for all parents for 10-12 weeks, and (2) one-to-one sessions with selected parents from the group-based element for up to 12 weeks. Methods/design: A randomised controlled trial will be conducted to evaluate Malachi's Inspiring Futures parenting programme. Participants will be allocated to one of two possible arms, with follow-up measures at 16 weeks (post-parent group programme) and at 32 weeks (post-one-to-one sessions with selected parents). The sample size is 248 participants with a randomisation allocation ratio of 1:1. The intervention arm will be offered the Inspiring Futures programme. The control group will receive services as usual. The aim is to determine the effectiveness of the Inspiring Futures programme on the primary outcome of behavioural and emotional difficulties of primary school children identified as having behavioural or emotional difficulties. Discussion: This study will further enhance the evidence for early intervention parenting programmes for child behavioural and emotional problems in the UK

    Prospectus, October 17, 1984

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    SPORTS FEATURE LADY COBRAS TAKE IV INVITATIONAL; Assistance available; many services offered; Speech team takes honors; Goal is to overthrow the \u27masculine mind\u27; PC Happenings; Parkland hosts Foley exhibit; TV for Parents and Kids debuts; Workshop focuses on sexual abuse of young children; Career restructuring focus of workshop; Hearing topic for retirees; International students enrich us all; Did You Know...; Creative Corner...Especially for you!!; Paper Dolls Souls; History; Depression; Alone; Being & Becoming; So Much; Breakable Item; Thumbism; Diary; \u27Doom Story\u27-the terror escalates; Excerpts from Some Late Evening Thoughts While Anticipating That First Great Thunderstorm of a Dry Month; Midnight; Strength or weakness; The Ultimate Weapon; Photographer captures essence of traditional, contemporary Latin America; Celebrate the Arts Week; WPCD DJ likes job, Parkland; TV programs for parents scheduled; Classifieds; Peter Pan syndrome causes relationship problems; Experience Blues Explosion; Two comedians better than one; 1978 was cruel summer for Sullivan; 1984 is proving to be a sweet fall; Drive on to educate-issues important; Powell wins invitational; Stewart places 4th; Peterson prefers to use an eight-ironhttps://spark.parkland.edu/prospectus_1984/1008/thumbnail.jp

    Characterization of disease course and remission in early seropositive rheumatoid arthritis: results from the TACERA longitudinal cohort study

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    Background: To characterise disease course and remission in a longitudinal observational study of newly diagnosed, initially treatment-naïve patients with seropositive rheumatoid arthritis (RA). Methods: Patients with early untreated seropositive RA were recruited from 28 UK centres. Multiple clinical and laboratory measures were collected every 3 months for up to 18 months. Disease activity was measured using the 28-joint Disease Activity Score with C-reactive protein (DAS28-CRP) and Simplified Disease Activity Index (SDAI). Logistic regression models examined clinical predictors of 6-month remission and latent class mixed models characterised disease course. Results: We enrolled 275 patients of whom 267 met full eligibility and provided baseline data. According to SDAI definition, 24.3% attained 6-month remission. Lower baseline Health Assessment Questionnaire (HAQ) and SDAI predicted 6-month remission (p = 0.013 and 0.011). Alcohol intake and baseline prescribing of methotrexate with a second disease-modifying antirheumatic drug (DMARD; vs monotherapy without glucocorticoids) were also predictive. Three distinct SDAI trajectory subpopulations emerged; corresponding to an inadequate responder group (6.5%), and higher and lower baseline activity responder groups (22.4% and 71.1%). Baseline HAQ and Short Form-36 Health Survey – Mental Component Score (SF-36 MCS) distinguished these groups. In addition, a number of baseline clinical predictors correlated with disease activity severity within subpopulations. Beneficial effects of alcohol intake were found across subpopulations. Conclusion: Three distinct disease trajectory subpopulations were identified. Differential effects of functional and mental well-being, alcohol consumption, and baseline RA medication prescribing on disease activity severity were found across subpopulations. Heterogeneity across trajectories cannot be fully explained by baseline clinical predictors. We hypothesise that biological markers collected early in disease course (within 6 months) may help patient management and better targeting of existing and novel therapies

    Cold gas accretion in galaxies

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    Evidence for the accretion of cold gas in galaxies has been rapidly accumulating in the past years. HI observations of galaxies and their environment have brought to light new facts and phenomena which are evidence of ongoing or recent accretion: 1) A large number of galaxies are accompanied by gas-rich dwarfs or are surrounded by HI cloud complexes, tails and filaments. It may be regarded as direct evidence of cold gas accretion in the local universe. It is probably the same kind of phenomenon of material infall as the stellar streams observed in the halos of our galaxy and M31. 2) Considerable amounts of extra-planar HI have been found in nearby spiral galaxies. While a large fraction of this gas is produced by galactic fountains, it is likely that a part of it is of extragalactic origin. 3) Spirals are known to have extended and warped outer layers of HI. It is not clear how these have formed, and how and for how long the warps can be sustained. Gas infall has been proposed as the origin. 4) The majority of galactic disks are lopsided in their morphology as well as in their kinematics. Also here recent accretion has been advocated as a possible cause. In our view, accretion takes place both through the arrival and merging of gas-rich satellites and through gas infall from the intergalactic medium (IGM). The infall may have observable effects on the disk such as bursts of star formation and lopsidedness. We infer a mean ``visible'' accretion rate of cold gas in galaxies of at least 0.2 Msol/yr. In order to reach the accretion rates needed to sustain the observed star formation (~1 Msol/yr), additional infall of large amounts of gas from the IGM seems to be required.Comment: To appear in Astronomy & Astrophysics Reviews. 34 pages. Full-resolution version available at http://www.astron.nl/~oosterlo/accretionRevie

    Does Sex Trade with Violence among Genotypes in Drosophila melanogaster?

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    The evolutionary forces shaping the ability to win competitive interactions, such as aggressive encounters, are still poorly understood. Given a fitness advantage for competitive success, variance in aggressive and sexual display traits should be depleted, but a great deal of variation in these traits is consistently found. While life history tradeoffs have been commonly cited as a mechanism for the maintenance of variation, the variability of competing strategies of conspecifics may mean there is no single optimum strategy. We measured the genetically determined outcomes of aggressive interactions, and the resulting effects on mating success, in a panel of diverse inbred lines representing both natural variation and artificially selected genotypes. Males of one genotype which consistently lost territorial encounters with other genotypes were nonetheless successful against males that were artificially selected for supernormal aggression and dominated all other lines. Intransitive patterns of territorial success could maintain variation in aggressive strategies if there is a preference for territorial males. Territorial success was not always associated with male mating success however and females preferred ‘winners’ among some male genotypes, and ‘losers’ among other male genotypes. This suggests that studying behaviour from the perspective of population means may provide limited evolutionary and genetic insight. Overall patterns of competitive success among males and mating transactions between the sexes are consistent with mechanisms proposed for the maintenance of genetic variation due to nonlinear outcomes of competitive interactions

    A chemical survey of exoplanets with ARIEL

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    Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 ÎŒm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio
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