397 research outputs found

    A bistable soft gripper with mechanically embedded sensing and actuation for fast closed-loop grasping

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    Soft robotic grippers are shown to be high effective for grasping unstructured objects with simple sensing and control strategies. However, they are still limited by their speed, sensing capabilities and actuation mechanism. Hence, their usage have been restricted in highly dynamic grasping tasks. This paper presents a soft robotic gripper with tunable bistable properties for sensor-less dynamic grasping. The bistable mechanism allows us to store arbitrarily large strain energy in the soft system which is then released upon contact. The mechanism also provides flexibility on the type of actuation mechanism as the grasping and sensing phase is completely passive. Theoretical background behind the mechanism is presented with finite element analysis to provide insights into design parameters. Finally, we experimentally demonstrate sensor-less dynamic grasping of an unknown object within 0.02 seconds, including the time to sense and actuate

    On Intrinsic Safety of Soft Robots

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    The rapidly growing field of soft robotics owes its success to the vast vistas of possibilities they promise. They may be utilized as standalone systems or work in harmony with the existing robotic technologies. Being based on soft and/or flexible materials, soft robots have usually high dexterity and, at the same time, they are also often considered "intrinsically safe." This is generally true and soft-bodied robots can be considered safer from a mechanical point of view, but this is sometimes improperly used. The identification of possible safety loopholes in soft robots is the subject of this paper. After a general overview of safety in robotics, we reported an overview of the main sources of unsafe conditions that may arise by the use of soft robotics technologies. Safety aspects are discussed in three categories: quasi-static, dynamic, and material failure. Some safety factors exclusive to soft robots such as whiplash-like effect and energy stored in highly strained elements are also introduced. Measures to avoid such unsafe conditions are presented such as establishing operational limits and introduction of inspection regimes and arrest systems

    Association between a single nucleotide polymorphism in neuregulin-1 and schizophrenia in Pakistani patients

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    Objective: To determine the association of single-nucleotide polymorphism8nrg433E1006 in the neuregulin-1 gene associated with schizophrenia.Methods: This case-control study was conducted at the Fountain House, Lahore, and the psychiatric clinics at the Aga Khan University, Karachi, from 2010 to 2013.The total genomic deoxyribonucleic acid was isolated and single-nucleotide polymorphism8nrg433E1006 was screened by nested polymerase chain reaction followed by sequencing. These sequences, from patients and controls, were aligned with the human neuregulin-1-glial growth factor 2 gene sequence, which served as a reference sequence. The single nucleotide polymorphism genetic algorithm was characterised at position 433 in the neuregulin-1 gene by aligning test and control sequences with the neuregulin-1-glial growth factor 2reference sequence using ClustalW algorithm, implemented in the BioEdit software.Results: Of the 630 samples, 321(51%) were of cases and 309(49%)of controls. Moreover, 99(30.8%) cases and 79(25.6%) controls rendered correct neuregulin-1 gene frames. Of them, the single-nucleotide polymorphism8nrg433E1006 was present in 62(62.6%) cases and 24(30.4%) controls. The analysis showed that the odds ratio of having schizophrenia is 3.8 times higher in the presence of this single-nucleotide polymorphism at the 92 bp of neuregulin-1 gene with the 95% confidence interval(p=0.0001).Conclusions: There was a strong association of single-nucleotide polymorphism8nrg433E1006 in the neuregulin-1 gene with schizophrenia

    DETECTION AND CHARACTERIZATION OF LATENCY STAGE OF EBV AND HISTOPATHOLOGICAL ANALYSIS OF PROSTATIC ADENOCARCINOMA TISSUES

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    The pathophysiology of prostate cancer involves both genetic and acquired factors, including pathogens, such as viruses. A limited number of studies have shown the presence of Epstein-Barr virus (EBV) in prostate cancer tissues. However, there is a dearth of data exploring EBV latency profile in prostate cancer, and the relationship of EBV with histopathological features of prostate cancer. In this study, prostate cancer and benign prostatic hyperplasia (BPH) samples were screened for the presence of EBV, followed by the characterization of the EBV latency profile and analysis of histopathological parameters in EBV-positive and EBV-negative groups. A conventional PCR strategy was employed using virus-specific primers to screen EBV in 99 formalin-fixed paraffin-embedded (FFPE) prostate cancer and 33 BPH samples received for histopathological analysis during the years 2019–2020. Subsequently, cDNA samples were used in a qPCR array to analyze the expression of EBV latency-associated genes to map the latency profile EBV maintains in the samples. Finally, statistical analyses were performed to determine the correlation between EBV and several histopathological features of the samples. EBV was detected in 39% of prostate cancer and 24% of BPH samples. The histopathological analysis of prostate cancer samples identified all samples as prostatic adenocarcinoma of acinar type, while statistical analyses revealed EBV-positive samples to exhibit significantly higher (p < 0.05) Gleason major and total Gleason scores as compared to EBV-negative samples. In the EBV-positive samples, variable expression patterns of latency-associated genes were observed, where most of the samples exhibited EBV latency II/III-like profiles in prostate cancer, while latency-II-like profiles in BPH samples. This study suggests a high prevalence of EBV in prostate samples, where EBV exhibited latency II/III-like profiles. Furthermore, EBV-positive samples exhibited a higher Gleason score suggesting a possible link between EBV and the onset/progression of prostate cancers. However, future functional studies are required to understand the role of the EBV gene expression profile in the onset/progression of prostate cancer

    Thermoelasticity and ArUco marker-based model validation of polymer structure: application to the San Giorgio's bridge inspection robot

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    Experimental procedures are often involved in the numerical models validation. To define the behaviour of a structure, its underlying dynamics and stress distributions are generally investigated. In this research, a multi-instrumental and multi-spectral method is proposed in order to validate the numerical model of the Inspection Robot mounted on the new San Giorgio's Bridge on the Polcevera river. An infrared thermoelasticity-based approach is used to measure stress-concentration factors and, additionally, an innovative methodology is implemented to define the natural frequencies of the Robot Inspection structure, based on the detection of ArUco fiducial markers. Established impact hammer procedure is also performed for the validation of the results.</p

    Measurement of the W-boson mass in pp collisions at s√=7TeV with the ATLAS detector

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    A measurement of the mass of the W boson is presented based on proton–proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC, and corresponding to 4.6 fb−1 of integrated luminosity. The selected data sample consists of 7.8×106 candidates in the → channel and 5.9×106 candidates in the → channel. The W-boson mass is obtained from template fits to the reconstructed distributions of the charged lepton transverse momentum and of the W boson transverse mass in the electron and muon decay channels, yielding =80370=80370±7 (stat.)±11(exp. syst.)±14 (mod. syst.) MeV±19MeV, where the first uncertainty is statistical, the second corresponds to the experimental systematic uncertainty, and the third to the physics-modelling systematic uncertainty. A measurement of the mass difference between the + and − bosons yields +−−=−29±28 MeV.publishedVersio

    Measurement of the tt¯ tt¯ production cross section in pp collisions at √s = 13 TeV with the ATLAS detector

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    A measurement of four-top-quark production using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider corresponding to an integrated luminosity of 139 fb−1 is presented. Events are selected if they contain a single lepton (electron or muon) or an opposite-sign lepton pair, in association with multiple jets. The events are categorised according to the number of jets and how likely these are to contain b-hadrons. A multivariate technique is then used to discriminate between signal and background events. The measured four-top-quark production cross section is found to be 26+17−15 fb, with a corresponding observed (expected) significance of 1.9 (1.0) standard deviations over the background-only hypothesis. The result is combined with the previous measurement performed by the ATLAS Collaboration in the multilepton final state. The combined four-top-quark production cross section is measured to be 24+7−6 fb, with a corresponding observed (expected) signal significance of 4.7 (2.6) standard deviations over the background-only predictions. It is consistent within 2.0 standard deviations with the Standard Model expectation of 12.0 ± 2.4 fb.publishedVersio

    Search for new phenomena with top quark pairs in final states with one lepton, jets, and missing transverse momentum in pp collisions at √s = 13 TeV with the ATLAS detector

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    A search for new phenomena with top quark pairs in final states with one isolated electron or muon, multiple jets, and large missing transverse momentum is performed. Signal regions are designed to search for two-, three-, and four-body decays of the directly pair-produced supersymmetric partner of the top quark (stop). Additional signal regions are designed specifically to search for spin-0 mediators that are produced in association with a pair of top quarks and decay into a pair of dark-matter particles. The search is performed using the Large Hadron Collider proton-proton collision dataset at a centre-of-mass energy of √s = 13 TeV recorded by the ATLAS detector from 2015 to 2018, corresponding to an integrated luminosity of 139 fb−1. No significant excess above the Standard Model background is observed, and limits at 95% confidence level are set in the stop-neutralino mass plane and as a function of the mediator mass or the dark-matter particle mass. Stops are excluded up to 1200 GeV (710 GeV) in the two-body (three-body) decay scenario. In the four-body scenario stops up to 640 GeV are excluded for a stop-neutralino mass difference of 60 GeV. Scalar and pseudoscalar dark-matter mediators are excluded up to 200 GeV when the coupling strengths of the mediator to Standard Model and dark-matter particles are both equal to one and when the mass of the dark-matter particle is 1 GeV.publishedVersio

    Search for the Higgs boson decays H → ee and H → eμ in pp collisions at √s=13 TeV with the ATLAS detector

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    Searches for the Higgs boson decays H → ee and H → eμ are performed using data corresponding to an integrated luminosity of 139 fb−1 collected with the ATLAS detector in pp collisions at √s = 13 TeV at the LHC. No significant signals are observed, in agreement with the Standard Model expectation. For a Higgs boson mass of 125 GeV, the observed (expected) upper limit at the 95% confidence level on the branching fraction B(H → ee) is 3.6 × 10−4 (3.5 × 10−4) and on B(H → eμ) is 6.2 × 10−5 (5.9 × 10−5). These results represent improvements by factors of about five and six on the previous best limits on B(H → ee) and B(H → eμ) respectively.publishedVersio

    Search for lepton-flavor violation in Z-boson decays with τ leptons with the ATLAS detector

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    A search for lepton-flavor-violating Z→eτ and Z→μτ decays with pp collision data recorded by the ATLAS detector at the LHC is presented. This analysis uses 139  fb−1 of Run 2 pp collisions at √s=13 TeV and is combined with the results of a similar ATLAS search in the final state in which the τ lepton decays hadronically, using the same data set as well as Run 1 data. The addition of leptonically decaying τ leptons significantly improves the sensitivity reach for Z→ℓτ decays. The Z→ℓτ branching fractions are constrained in this analysis to B(Z→eτ)<7.0×10−6 and B(Z→μτ)<7.2×10−6 at 95% confidence level. The combination with the previously published analyses sets the strongest constraints to date: B(Z→eτ)<5.0×10−6 and B(Z→μ)<6.5×10−6 at 95% confidence level.publishedVersio
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