Fabrication of a Cell Electrostimulator Using Pulse Laser Deposition and Laser Selective Thin Film Removal

In this work, we present a laser-based process for fabricating a cell electrostimulator. The fabrication methodology comprises two laser processes: a pulse laser deposition (PLD) of an aluminum thin film on soda-lime glass and a laser-based selectively removal of the thin film. The laser set-up for PLD consist of Nd:YVO4 Rofin Power line 20E (1064 nm wavelength, 20 ns pulse width) focused by a lens of 160 mm focal length inside a vacuum chamber to strike a target of the deposited material. The same laser is used for selectively removing the thin film but focused by a lens of 100 mm focal length. The geometry design is made in CAD-like software. Before microfabrication, a thin aluminum layer (1 μm thickness) is deposited on soda-lime glass using the PLD method. In order to assemble the device, the electrical stimulator is placed between two polycarbonate sheets of 1.5 mm thickness. To prevent any contact with the electric circuit, a thin silicate glass (100 μm) is placed over the electrostimulator. Simulations were performed using ANSYS Maxwell software, verifying that the induced electrical field achieves the minimum for cell stimulation

Bioelectronics-on-a-chip for cardio myoblast proliferation enhancement using electric field stimulation

Background: Cardio myoblast generation from conventional approaches is laborious and time-consuming. We present a bioelectronics on-a-chip for stimulating cells cardio myoblast proliferation during culture. Method: The bioelectronics chip fabrication methodology involves two different process. In the first step, an aluminum layer of 200 nm is deposited over a soda-lime glass substrate using physical vapor deposition and selectively removed using a Q-switched Nd:YVO4 laser to create the electric tracks. To perform the experiments, we developed a biochip composed of a cell culture chamber fabricated with polydimethylsiloxane (PDMS) with a glass coverslip or a cell culture dish placed over the electric circuit tracks. By using such a glass cover slip or cell culture dish we avoid any toxic reactions caused by electrodes in the culture or may be degraded by electrochemical reactions with the cell medium, which is crucial to determine the effective cell-device coupling. Results: The chip was used to study the effect of electric field stimulation of Rat ventricular cardiomyoblasts cells (H9c2). Results shows a remarkable increase in the number of H9c2 cells for the stimulated samples, where after 72 h the cell density double the cell density of control samples. Conclusions: Cell proliferation of Rat ventricular cardiomyoblasts cells (H9c2) using the bioelectronics-on-a-chip was enhanced upon the electrical stimulation. The dependence on the geometrical characteristics of the electric circuit on the peak value and homogeneity of the electric field generated are analyzed and proper parameters to ensure a homogeneous electric field at the cell culture chamber are obtained. It can also be observed a high dependence of the electric field on the geometry of the electrostimulator circuit tracks and envisage the potential applications on electrophysiology studies, monitoring and modulate cellular behavior through the application of electric fieldsThis work was partially supported by Mineco through the projects FIS 2015–71933-REDT and RTI 2018–097063-B-I00, Consellería de Educación Program for Development of a Strategic Grouping in Materials – AeMAT Grant No. ED431E2018/08, Xunta de Galicia ref. ED431B2017/64. Xunta de Galicia, Spain, under Galician Programme for Research Innovation and Growth 2011–2015 (I2C Plan)S

Study of the kinematic dependences of Λ 0b production in pp collisions and a measurement of the Λ 0b → Λ +c π − branching fraction

The kinematic dependences of the relative production rates, fΛ0b/fd, of Λ 0b baryons and B 0 mesons are measured using Λ 0b → Λ +c π − and B¯0 →D+π− decays. The measurements use proton-proton collision data, corresponding to an integrated luminosity of 1 fb−1 at a centre-of-mass energy of 7 TeV, recorded in the forward region with the LHCb experiment. The relative production rates are observed to depend on the transverse momentum, p T, and pseudorapidity, η, of the beauty hadron, in the studied kinematic region 1.5 < p T < 40 GeV/c and 2 < η < 5. Using a previous LHCb measurement of fΛ0b/fd in semileptonic decays, the branching fraction ℬ(Λ 0b → Λ +c π −) = (4.30 ± 0.03 + 0.12− 0.11 ± 0.26 ± 0.21) × 10− 3 is obtained, where the first uncertainty is statistical, the second is systematic, the third is from the previous LHCb measurement of fΛ0b/fd and the fourth is due to the b B¯0 →D+π− branching fraction. This is the most precise measurement of a Λ 0b branching fraction to date.S

Search for the decay D0→π+π−μ+μ−

A search for the D0→π+π−μ+μ− decay, where the muon pair does not originate from a resonance, is performed using proton–proton collision data corresponding to an integrated luminosity of 1.0 fb−1 recorded by the LHCb experiment at a centre-of-mass energy of 7 TeV. No signal is observed and an upper limit on the relative branching fraction with respect to the resonant decay mode D0→π+π− φ(→μ+μ− ), under the assumption of a phase-space model, is found to be B D0→π + π − μ + μ − /B D0→π + π − φ →μ + μ − < 0.96 at 90% confidence level. The upper limit on the absolute branching fraction is evaluated to be B(D0→π+π−μ+μ− ) < 5.5×10−7 at 90% confidence level. This is the most stringent to date.S

Evidence for the decay X(3872) →ψ(2S)γ

Evidence for the decay mode X(3872) →ψ(2S)γin B+→X(3872)K+decays is found with a sig-nificance of 4.4 standard deviations. The analysis is based on adata sample of proton–proton collisions, corresponding to an integrated luminosity of3fb−1, collected with the LHCb detector, at centre-of-mass energies of 7and8TeV. The ratio of the branching fraction of the X(3872) →ψ(2S)γdecay to that of the X(3872) →J/ψγdecay is measured to be B(X(3872)→ψ(2S)γ) B(X(3872)→J/ψγ) = 2.46± 0.64±0.29, where the first uncertainty is statistical and the second is systematic. The measured value does not support apureD¯ D∗molecular interpretation of the X(3872)state.S

A study of CP violation in B± →DK± and B±→Dπ± decays with D→K0SK±π∓ final states

A first study of CP violation in the decay modes B±→[KS 0 K±π∓] D h±and B±→[KS 0 K∓ π±] D h±, where h labels a K or π meson and D labels a D 0 or D‾ 0 meson, is performed. The analysis uses the LHCb data set collected in pp collisions, corresponding to an integrated luminosity of 3 fb− 1. The analysis is sensitive to the CP-violating CKM phase γ through seven observables: one charge asymmetry in each of the four modes and three ratios of the charge-integrated yields. The results are consistent with measurements of γ using other decay modesS

Measurement of the B+c meson lifetime using B+c→J/ψμ+νμX decays

The lifetime of the B+c meson is measured using semileptonic decays having a J/ψ meson and a muon in the final state. The data, corresponding to an integrated luminosity of 2 fb −1, are collected by the LHCb detector in pp collisions at a centre-of-mass energy of 8 TeV. The measured lifetime is τ=509±8±12 fs, where the first uncertainty is statistical and the second is systematic.S

Search for CP violation in the decay D+→π−π+π+

A search for CP violation in the phase space of the decay D+→π−π+π+ is reported using pp collision data, corresponding to an integrated luminosity of 1.0 fb−1, collected by the LHCb experiment at a centreof- mass energy of 7 TeV. The Dalitz plot distributions for 3.1×106 D+ and D− candidates are compared with binned and unbinned model-independent techniques. No evidence for CP violation is foundS

Measurement of the flavour-specific CP-violating asymmetry assl in B0s decays

The CP-violating asymmetry as sl is studied using semileptonic decays of B0s and B0s mesons produced in pp collisions at a centre-of-mass energy of 7 TeV at the LHC, exploiting a data sample corresponding to an integrated luminosity of 1.0 fb−1. The reconstructed final states are D± s μ∓, with the D± s particle decaying in the φπ± mode. The D± s μ∓ yields are summed over B0s and B0s initial states, and integrated with respect to decay time. Data-driven methods are used to measure efficiency ratios. We obtain as sl = (−0.06±0.50±0.36)%, where the first uncertainty is statistical and the second systematic.S