29 research outputs found

    A novel hybrid method of β-turn identification in protein using binary logistic regression and neural network

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    From both the structural and functional points of view, β-turns play important biological roles in proteins. In the present study, a novel two-stage hybrid procedure has been developed to identify β-turns in proteins. Binary logistic regression was initially used for the first time to select significant sequence parameters in identification of β-turns due to a re-substitution test procedure. Sequence parameters were consisted of 80 amino acid positional occurrences and 20 amino acid percentages in sequence. Among these parameters, the most significant ones which were selected by binary logistic regression model, were percentages of Gly, Ser and the occurrence of Asn in position i+2, respectively, in sequence. These significant parameters have the highest effect on the constitution of a β-turn sequence. A neural network model was then constructed and fed by the parameters selected by binary logistic regression to build a hybrid predictor. The networks have been trained and tested on a non-homologous dataset of 565 protein chains. With applying a nine fold cross-validation test on the dataset, the network reached an overall accuracy (Qtotal) of 74, which is comparable with results of the other β-turn prediction methods. In conclusion, this study proves that the parameter selection ability of binary logistic regression together with the prediction capability of neural networks lead to the development of more precise models for identifying β-turns in proteins

    Parton Distribution Functions of the Charged Pion Within The xFitter Framework

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    We present the first open-source analysis of parton distribution functions (PDFs) of charged pions using xFitter, an open-source QCD fit framework to facilitate PDF extraction and analyses. Our calculations are implemented at next-to-leading order (NLO) using APPLgrids generated by MCFM generator. Using currently available Drell-Yan and photon production data, we find the valence distribution is well constrained; however, the considered data are not sensitive enough to unambiguously determine sea and gluon distributions. Fractions of momentum carried by the valence, sea and gluon components are discussed, and we compare with the results of JAM collaboration and the GRV group.Comment: 9 pages, 6 figure

    Exploring SMEFT Couplings Using the Forward-Backward Asymmetry in Neutral Current Drell-Yan Production at the LHC

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    Neutral current Drell-Yan (DY) lepton-pair production is considered in the framework of the Standard Model Effective Field Theory (SMEFT). Using the open-source fit platform xFitter, we investigate the impact of high-statistics measurements of the neutral current DY (NCDY) forward-backward asymmetry AFBA_{\rm{FB}} near the weak boson mass scale in the present and forthcoming stages of the Large Hadron Collider (LHC). Besides recovering earlier results on the AFBA_{\rm{FB}} sensitivity to parton distribution functions, we analyze the precision determination of ZZ-boson couplings to left-handed and right-handed uu-quarks and dd-quarks, and explore Beyond-Standard-Model contributions using the SMEFT framework. We comment on the role of the AFBA_{\rm{FB}} asymmetry for the electroweak SMEFT fit and precision ZZ-boson physics at the LHC and high-luminosity HL-LHC

    QCD analysis of pion fragmentation functions in the xFitter framework

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    We present the first open-source analysis of fragmentation functions (FFs) of charged pions (entitled IPM-xFitter) computed at next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) accuracy in perturbative QCD using the xFitter framework. This study incorporates a comprehensive and up-to-date set of pion production data from single-inclusive annihilation (SIA) processes, as well as the most recent measurements of inclusive cross-sections of single pion by the BELLE collaboration. The determination of pion FFs along with their theoretical uncertainties is performed in the Zero-Mass Variable-Flavor Number Scheme (ZM-VFNS). We also present comparisons of our FFs set with recent fits from the literature. The resulting NLO and NNLO pion FFs provide valuable insights for applications in present and future high-energy analysis of pion final state processes

    Interacting viscous ghost tachyon, K-essence and dilaton scalar field models of dark energy

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    We study the correspondence between the interacting viscous ghost dark energy model with the tachyon, K-essence and dilaton scalar field models in the framework of Einstein gravity. We consider a spatially non-flat FRW universe filled with interacting viscous ghost dark energy and dark matter. We reconstruct both the dynamics and potential of these scalar field models according to the evolutionary behavior of the interacting viscous ghost dark energy model, which can describe the accelerated expansion of the universe. Our numerical results show that the interaction and viscosity have opposite effects on the evolutionary properties of the ghost scalar filed models.Comment: 16 pages, 17 figure

    First NNLO fragmentation functions of K0S and Lambda and their uncertainties in the presence of hadron mass corrections

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    The current paper presents a determination of K^0_SK S0 and \Lambda/\bar{\Lambda}Λ/ Λ ˉ fragmentation functions (FFs) from QCD analysis of single-inclusive electron-positron annihilation process (SIA). Our FFs determinations are performed at next-to-leading order (NLO), and for the first time, at next-to-next-to-leading order (NNLO) accuracy in perturbative Quantum Chromodynamics (pQCD) which is designated as {\tt SAK20} FFs. Each of these FFs is accompanied by their uncertainties which are determined using the `Hessian' method. Considering the hadron mass corrections, we clearly investigate the reliability of our results upon the inclusion of higher-order QCD correction. We provide comparisons of {\tt SAK20} FFs set with the available analysis from another group, finding in general a reasonable agreement, and also considerable differences. In order to judge the fit quality, our theoretical predictions are compared with the analyzed SIA datasets. {\tt SAK20} FFs at NLO and NNLO accuracy along with their uncertainties are made available in the standard {\tt LHAPDF} format in order to use for predictions of present and future measurements in high-energy collisions such as LHC and RHIC

    Inkjet-printed flexible piezoelectric sensor for self-powered biomedical monitoring

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    Printed electronics has opened up new insights towards fabrication of electronic components and devices. This manufacturing technique has been successfully employed as a complementary fabrication approach to conventional nanolithography and microfabrication processes to create flexible and stretchable electronics. Fluoropolymers are crucial components in electronic manufacturing, owing to their piezoelectric, triboelectric, pyroelectric, ferroelectric, and dielectric properties. In this research, we report fabrication of an inkjet-printed piezoelectric sensor based on poly(vinylidenefluoride trifluoroethylene) (PVDF-TrFE) and amine functionalized graphene oxide (AGO) for biomedical monitoring. The piezoelectric inkjet ink was obtained by optimizing the fluid mechanic properties based on Reynold and Weber numbers. The inkjet-printed freestanding film was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), wide-angle X-Ray scattering (WAXS), and differential scanning calorimetry (DSC). The piezoelectric sensor was fabricated out of the printed film by painting electrodes on each side, followed by wiring and encapsulation. The sensor was subjected to an electric field of 1500 kV/cm to align the internal dipoles and induce a net polarization. The obtained flexible piezoelectric sensor was employed for monitoring biomedical signals such as finger tapping, joint bending, and swallowing
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