Endoscopic Tactile Capsule for Non-Polypoid Colorectal Tumour Detection

An endoscopic tactile robotic capsule, embedding miniaturized MEMS force sensors, is presented. The capsule is conceived to provide automatic palpation of non-polypoid colorectal tumours during colonoscopy, since it is characterized by high degree of dysplasia, higher invasiveness and lower detection rates with respect to polyps. A first test was performed employing a silicone phantom that embedded inclusions with variable hardness and curvature. A hardness-based classification was implemented, demonstrating detection robustness to curvature variation. By comparing a set of supervised classification algorithms, a weighted 3-nearest neighbor classifier was selected. A bias force normalization model was introduced in order to make different acquisition sets consistent. Parameters of this model were chosen through a particle swarm optimization method. Additionally, an ex-vivo test was performed to assess the capsule detection performance when magnetically-driven along a colonic tissue. Lumps were identified as voltage peaks with a prominence depending on the total magnetic force applied to the capsule. Accuracy of 94 % in hardness classification was achieved, while a 100 % accuracy is obtained for the lump detection within a tolerance of 5 mm from the central path described by the capsule. In real application scenario, we foresee our device aiding physicians to detect tumorous tissues

Criticality in diluted ferromagnet

We perform a detailed study of the critical behavior of the mean field diluted Ising ferromagnet by analytical and numerical tools. We obtain self-averaging for the magnetization and write down an expansion for the free energy close to the critical line. The scaling of the magnetization is also rigorously obtained and compared with extensive Monte Carlo simulations. We explain the transition from an ergodic region to a non trivial phase by commutativity breaking of the infinite volume limit and a suitable vanishing field. We find full agreement among theory, simulations and previous results.Comment: 23 pages, 3 figure

Search for the rare decay Λc+ →pμ+μ-

The flavor-changing neutral-current (FCNC) decay Λþ c → pμþμ− (inclusion of the charge-conjugate processes is implied throughout) is expected to be heavily suppressed in the Standard Model (SM) by the Glashow-IliopoulosMaiani mechanism [1]. The branching fractions for shortdistance c → ulþl− contributions to the transition are expected to be of Oð10−9Þ in the SM but can be enhanced by effects beyond the SM. However, long-distance contributions proceeding via a tree-level amplitude, with an intermediate meson resonance decaying into a dimuon pair [2,3], can increase the branching fraction up to Oð10−6Þ [4]. The short-distance and hadronic contributions can be separated by splitting the data set into relevant regions of dimuon mass. The Λþ c → pμþμ− decay has been previously searched for by the BABAR Collaboration [5], yielding 11.1 5.0 2.5 events and an upper limit on the branching fraction of 4.4 × 10−5 at 90% C.L. Similar FCNC transitions for the b-quark system (b → slþl−) exhibit a pattern of consistent deviations from the current SM predictions both in branching fractions [6] and angular observables [7], with the combined significance reaching 4 to 5 standard deviations [8,9]. Processes involving c → ulþl− transitions are far less explored at both the experimental and theoretical levels, which makes such measurements desirable. Similar analyses of the D system have reported evidence for the longdistance contribution [10]; however, the short-distance contributions have not been established [11]

Seedless hydrothermal growth of ZnO nanorods as a promising route for flexible tactile sensors

Hydrothermal growth of ZnO nanorods has been widely used for the development of tactile sensors, with the aid of ZnO seed layers, favoring the growth of dense and vertically aligned nanorods. However, seed layers represent an additional fabrication step in the sensor design. In this study, a seedless hydrothermal growth of ZnO nanorods was carried out on Au-coated Si and polyimide substrates. The effects of both the Au morphology and the growth temperature on the characteristics of the nanorods were investigated, finding that smaller Au grains produced tilted rods, while larger grains provided vertical rods. Highly dense and high-aspect-ratio nanorods with hexagonal prismatic shape were obtained at 75 °C and 85 °C, while pyramid-like rods were grown when the temperature was set to 95 °C. Finite-element simulations demonstrated that prismatic rods produce higher voltage responses than the pyramid-shaped ones. A tactile sensor, with an active area of 1 cm2, was fabricated on flexible polyimide substrate and embedding the nanorods forest in a polydimethylsiloxane matrix as a separation layer between the bottom and the top Au electrodes. The prototype showed clear responses upon applied loads of 2–4 N and vibrations over frequencies in the range of 20–800 Hz

A measurement of the CP asymmetry difference between Λc + → pK − K + and pπ−π+ decays

The difference between the CP asymmetries in the decays Λ + c → pK−K+ and Λ + c → pπ−π + is presented. Proton-proton collision data taken at centre-of-mass energies of 7 and 8 TeV collected by the LHCb detector in 2011 and 2012 are used, corresponding to an integrated luminosity of 3 fb−1 . The Λ + c candidates are reconstructed as part of the Λ 0 b → Λ + c µ −X decay chain. In order to maximize the cancellation of production and detection asymmetries in the difference, the final-state kinematic distributions of the two samples are aligned by applying phase-space-dependent weights to the Λ + c → pπ−π + sample. This alters the definition of the integrated CP asymmetry to A wgt CP (pπ−π +). Both samples are corrected for reconstruction and selection efficiencies across the five-dimensional Λ + c decay phase space. The difference in CP asymmetries is found to be ∆A wgt CP = ACP (pK−K+) − A wgt CP (pπ−π +) = (0.30 ± 0.91 ± 0.61) %, where the first uncertainty is statistical and the second is systemati

Свободные аминокислоты и их азотсодержащие метаболиты в гипоталамусе крыс при острой интоксикации динилом и их корреляция с аминокислотным спектром плазмы крови

аминокислотыгипоталамусдинилотравлениеплазм

Angular moments of the decay Λb 0 → Λμ + μ − at low hadronic recoil

An analysis of the angular distribution of the decay Λ0 b → Λµ +µ − is presented, using data collected with the LHCb detector between 2011 and 2016 and corresponding to an integrated luminosity of approximately 5 fb−1 . Angular observables are determined using a moment analysis of the angular distribution at low hadronic recoil, corresponding to the dimuon invariant mass squared range 15 < q2 < 20 GeV2/c4 . The full basis of observables is measured for the first time. The lepton-side, hadron-side and combined forward-backward asymmetries of the decay are determined to b

Implementation of an epicardial implantable MEMS sensor for continuous and real-time postoperative assessment of left ventricular activity in adult minipigs over a short- and long-term period

The sensing of left ventricular (LV) activity is fundamental in the diagnosis and monitoring of cardiovascular health in high-risk patients after cardiac surgery to achieve better short- and long-term outcome. Conventional approaches rely on noninvasive measurements even if, in the latest years, invasive microelectromechanical systems (MEMS) sensors have emerged as a valuable approach for precise and continuous monitoring of cardiac activity. The main challenges in designing cardiac MEMS sensors are represented by miniaturization, biocompatibility, and long-term stability. Here, we present a MEMS piezoresistive cardiac sensor capable of continuous monitoring of LV activity over time following epicardial implantation with a pericardial patch graft in adult minipigs. In acute and chronic scenarios, the sensor was able to compute heart rate with a root mean square error lower than 2 BPM. Early after up to 1 month of implantation, the device was able to record the heart activity during the most important phases of the cardiac cycle (systole and diastole peaks). The sensor signal waveform, in addition, closely reflected the typical waveforms of pressure signal obtained via intraventricular catheters, offering a safer alternative to heart catheterization. Furthermore, histological analysis of the LV implantation site following sensor retrieval revealed no evidence of myocardial fibrosis. Our results suggest that the epicardial LV implantation of an MEMS sensor is a suitable and reliable approach for direct continuous monitoring of cardiac activity. This work envisions the use of this sensor as a cardiac sensing device in closed-loop applications for patients undergoing heart surgery

Observation of the decay Bs0→D¯0K+K−

The first observation of the B0 s → D¯ 0KþK− decay is reported, together with the most precise branching fraction measurement of the mode B0 → D¯ 0KþK−. The results are obtained from an analysis of pp collision data corresponding to an integrated luminosity of 3.0 fb−1. The data were collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The branching fraction of the B0 → D¯ 0KþK− decay is measured relative to that of the decay B0 → D¯ 0πþπ− to be BðB0→D¯ 0KþK−Þ BðB0→D¯ 0πþπ−Þ ¼ ð6.9 0.4 0.3Þ%, where the first uncertainty is statistical and the second is systematic. The measured branching fraction of the B0 s → D¯ 0KþK− decay mode relative to that of the corresponding B0 decay is BðB0 s→D¯ 0KþK−Þ BðB0→D¯ 0KþK−Þ ¼ ð93.0 8.9 6.9Þ%. Using the known branching fraction of B0 → D¯ 0πþπ−, the values of BðB0 →D¯ 0KþK−Þ¼ð6.10.40.30.3Þ×10−5 and BðB0 s →D¯ 0KþK−Þ¼ð5.70.50.40.5Þ×10−5 are obtained, where the third uncertainties arise from the branching fraction of the decay modes B0 → D¯ 0πþπ− and B0 → D¯ 0KþK−, respectively