1,728 research outputs found

    Spline regression for zero-inflated models

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    We propose a regression model for count data when the classical generalized linear model approach is too rigid due to a high outcome of zero counts and a nonlinear influence of continuous covariates. Zero-Inflation is applied to take into account the presence of excess zeros with separate link functions for the zero and the nonzero component. Nonlinearity in covariates is captured by spline functions based on B-splines. Our algorithm relies on maximum-likelihood estimation and allows for adaptive box-constrained knots, thus improving the goodness of the spline fit and allowing for detection of sensitivity changepoints. A simulation study substantiates the numerical stability of the algorithm to infer such models. The AIC criterion is shown to serve well for model selection, in particular if nonlinearities are weak such that BIC tends to overly simplistic models. We fit the introduced models to real data of children's dental sanity, linking caries counts with the so-called Body-Mass-Index (BMI) and other socioeconomic factors. This reveals a puzzling nonmonotonic influence of BMI on caries counts which is yet to be explained by clinical experts

    Deuterium induces a distinctive Escherichia coli proteome that correlates with the reduction in growth rate

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    Substitution of protium (H) for deuterium (D) strongly affects biological systems. Whereas higher eukaryotes such as plants and mammals hardly survive a deuterium content of > 30%, many microorganisms can grow on fully deuterated media, albeit at reduced rates. Very little is known about how the H/D replacement influences life at the systems level. Here, we used MS-based analysis to follow the adaptation of a large part of the; Escherichia coli; proteome from growth on a protonated full medium, over a protonated minimal medium, to a completely deuterated minimal medium. We could quantify > 1800 proteins under all conditions, several 100 of which exhibited strong regulation during both adaptation processes. The adaptation to minimal medium strongly up-regulated amino acid synthesis and sugar metabolism and down-regulated translational proteins on average by 9%, concomitant with a reduction in growth rate from 1.8 to 0.67 h; -1; In contrast, deuteration caused a very wide proteomic response over many cell functional categories, together with an additional down-regulation of the translational proteins by 5%. The latter coincided with a further reduction in growth rate to 0.37 h; -1; , revealing a clear linear correlation between growth rate and abundance of translational proteins. No significant morphological effects are observed under light and electron microscopy. Across all protein categories, about 80% of the proteins up-regulated under deuteration are enzymes with hydrogen transfer functions. Thus, the H/D kinetic isotope effect appears as the major limiting factor of cellular functions under deuteration

    Using airborne LiDAR Survey to explore historic-era archaeological landscapes of Montserrat in the eastern Caribbean

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    This article describes what appears to be the first archaeological application of airborne LiDAR survey to historic-era landscapes in the Caribbean archipelago, on the island of Montserrat. LiDAR is proving invaluable in extending the reach of traditional pedestrian survey into less favorable areas, such as those covered by dense neotropical forest and by ashfall from the past two decades of active eruptions by the SoufriĂšre Hills volcano, and to sites in localities that are inaccessible on account of volcanic dangers. Emphasis is placed on two aspects of the research: first, the importance of ongoing, real-time interaction between the LiDAR analyst and the archaeological team in the field; and second, the advantages of exploiting the full potential of the three-dimensional LiDAR point cloud data for purposes of the visualization of archaeological sites and features

    Transport properties of copper phthalocyanine based organic electronic devices

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    Ambipolar charge carrier transport in Copper phthalocyanine (CuPc) is studied experimentally in field-effect transistors and metal-insulator-semiconductor diodes at various temperatures. The electronic structure and the transport properties of CuPc attached to leads are calculated using density functional theory and scattering theory at the non-equilibrium Green's function level. We discuss, in particular, the electronic structure of CuPc molecules attached to gold chains in different geometries to mimic the different experimental setups. The combined experimental and theoretical analysis explains the dependence of the mobilityand the transmission coefficient on the charge carrier type (electrons or holes) and on the contact geometry. We demonstrate the correspondence between our experimental results on thick films and our theoretical studies of single molecule contacts. Preliminary results for fluorinated CuPc are discussed.Comment: 18 pages, 16 figures; to be published in Eur. Phys. J. Special Topic

    Tailoring surface properties, biocompatibility and corrosion behavior of stainless steel by laser induced periodic surface treatment towards developing biomimetic stents

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    Laser-Induced Periodic Surface Structures (LIPSS) holds great potential for regenerative biomedicine. Creating highly precise LIPSS enables to generate biomimetic implant surfaces with improved properties. The present study focuses on the fabrication and investigation of laser-treated stainless steel samples with applied linear LIPSS patterns with grooves made by means of a picosecond laser system using wavelengths of 1064 nm and 532 nm. To investigate properties of the laser-treated surfaces and to understand the basics of cell-surface interactions between the LIPSS and human Umbilical Cord Mesenchymal Stem Cells (UCMSC), flat stainless steel samples with various applied nanopatterns were used. Such LIPSSs demonstrated higher surface roughness, good biocompatibility, lower wettability and higher corrosion resistance compared to the untreated (polished) spec-imens. The surface roughness of laser-treated samples was in microscale that enabled adhesion and migration of endothelial cells, thus increasing the likelihood for endothelialisation. This thereby could reduce the chances for the development of Late Stent Thrombosis (LST) and In-Stent Restenosis (ISR). Furthermore, laser textured surfaces demonstrated an environment supportive for cell attachment, proliferation and alignment with the nanogroves. Therefore, application of the biomimetic nanopatterns could help to overcome frequent post-surgery complications after the stent implantation

    Metacarpophalangeal pattern profile analysis in fragile X syndrome

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    We analyzed the metacarpophalangeal pattern profile (MCPP) on 18 male individuals from 16 families with fragile X—fra (X), or Martin-Bell—syndrome and calculated a mean syndrome profile. Fourteen of 18 individuals with fra (X) syndrome had significant positive correlations which indicated clinical homogeneity. Discriminant analysis of individuals with fra (X) syndrome compared with a sample of normal individuals produced a correct classification rate of 88% based on a function of 3 MCPP variables that may provide a useful tool in screening individuals for the fra (X) syndrome. Discriminant and correlation analyses of individuals with Sotos sequence and individuals with fra (X) syndrome did not identify MCPP similarities. Therefore, there was no MCPP evidence in our study of patients with Sotos sequence and fra (X) chromosome expression

    A cognitive behavioural mHealth intervention for families in the postpartum period to enhance weight management, mental well-being and resilience : a study protocol for a randomised controlled trial (I‑PREGNO) : [version 1; peer review: awaiting peer review]

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    Introduction: The postpartum period goes along with an increased risk of unhealthy weight gain and numerous physical and psychological challenges, which are associated with mental well-being and resilience. Given the individual circumstances and the accompanying time constraints, evidence-based mHealth interventions may be useful for flexible, spot-on complementary care. Thus, the mHealth app I-PREGNO aims to enhance mental well-being and resilience by offering cognitive-behavioural and behaviour change skills training to prevent unhealthy weight development in this vulnerable life episode. In a randomised controlled trial, we will examine its effectiveness and acceptance. Protocol: Parents of infants between 0 and 12 months will be randomised to the intervention or control group. Both groups will take part in a baseline survey (t0) and further assessments after 12 weeks (intervention duration, t1), and 6 months (t2). The intervention group will use the self-guided mHealth app after t0 and both groups will get unlimited access after t2. The primary outcomes will be i) weight (difference of weight in kg after the intervention and pre-pregnancy); ii) mental well-being assessed through the Edinburgh-Postnatal-Depression-Scale and Parenting Stress Index; iii) resilience assessed through the General Self-Efficacy Scale and Difficulties in Emotion Regulation Scale. Secondary outcomes will be sociodemographic variables, eating behaviour, physical activity, relationship experiences, childhood trauma, postpartum bonding, regulatory disorders, and app usability. Gender differences between mothers and fathers will be considered. Conclusion: Positive effects on weight development in the postpartum period, mental well-being, and resilience due to the I-PREGNO intervention will support parental health in the critical postpartum phase. The study results will contribute to the growing field of evidence-based, highly scalable, low-cost, geographically independent, just-in-time mobile support for a target group that is restricted in time and resources. Trial registration: The trial has been registered at the German Clinical Trials Register (DRKS00031067) in January 2023 prospectively

    Fluorescent carbon dioxide indicators

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    Over the last decade, fluorescence has become the dominant tool in biotechnology and medical imaging. These exciting advances have been underpinned by the advances in time-resolved techniques and instrumentation, probe design, chemical / biochemical sensing, coupled with our furthered knowledge in biology. Complementary volumes 9 and 10, Advanced Concepts of Fluorescence Sensing: Small Molecule Sensing and Advanced Concepts of Fluorescence Sensing: Macromolecular Sensing, aim to summarize the current state of the art in fluorescent sensing. For this reason, Drs. Geddes and Lakowicz have invited chapters, encompassing a broad range of fluorescence sensing techniques. Some chapters deal with small molecule sensors, such as for anions, cations, and CO2, while others summarize recent advances in protein-based and macromolecular sensors. The Editors have, however, not included DNA or RNA based sensing in this volume, as this were reviewed in Volume 7 and is to be the subject of a more detailed volume in the near future
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