物理最新文献

Simplified protocol for quantitative FRET in living cells with direct QuanTI-FRET calibration from the images of interest

Genetically encoded biosensors based on the fluorescence resonance energy transfer (FRET) between two fluorescent proteins have the power to measure biochemical activity in living cells with the spatio-temporal resolution given by optical microscopy. The generalization of their usage is limited by the difficulties in obtaining quantitative results independent of the instrumental system or the expression level. We recently developed quantitative three-image FRET (QuanTI-FRET), a method for calibrating the system and obtaining absolute values of the FRET probabilities. The method proved to be efficient but required additional constructs for the calibration, thereby adding experimental steps. Here, we propose taking advantage of the constant and known stoichiometry of intramolecular FRET biosensors to directly calibrate the system using the dataset of interest, e.g., biosensor experiments. We demonstrate this idea by comparing the results of both standard calibration and autocalibration obtained on live-cell images of the FAK biosensor. This autocalibration is possible because of the strong robustness of the QuanTI-FRET calibration with respect to the quality of the calibration dataset. With this work, we simplify the experimental protocol to obtain quantitative FRET by autocalibration, and we make it accessible through a publicly available Python software and a napari plug-in.

Graphical abstract

Simplified protocol for quantitative FRET in living cells with direct QuanTI-FRET calibration from the images of interest

Bayesian analysis results require a choice of prior distribution. In long-baseline neutrino oscillation physics, the usual parameterisation of the mixing matrix induces a prior that privileges certain neutrino mass and flavour state symmetries. Here we study the effect of privileging alternate symmetries on the results of the T2K experiment. We find that constraints on the level of CP violation (as given by the Jarlskog invariant) are robust under the choices of prior considered in the analysis. On the other hand, the degree of octant preference for the atmospheric angle depends on which symmetry has been privileged.

This study presents the fabrication and optimization of fluorine-free silica-based thin films with tunable wettability for self-cleaning applications. Silica nanoparticles were synthesized via a sol–gel spin-coating process using tetraethyl orthosilicate (TEOS) as the precursor, followed by thermal annealing in an air ambient and surface modification using hexamethyldisilazane (HMDS). The influence of TEOS concentration and annealing temperature on nanoparticle size, surface morphology, and wettability was systematically investigated. Structural study by X-ray diffraction technique for all the samples illustrated an amorphous structure of silica thin films with a broad peak around 24^ο without shifting the peak position. Field emission scanning electron microscopy (FESEM) revealed that increased TEOS concentration led to larger particle sizes and enhanced surface roughness. Fourier-transform infrared spectroscopy (FTIR) confirmed successful salinization, and UV-vis spectroscopy showed moderate optical transparency (45%) in the visible/UV-Vis range. Contact angle measurements demonstrated a transition from hydrophilic to superhydrophobic behaviour (up to ~ 139°), governed by surface roughness and chemical modification. The results indicate that the size of the synthesized nanoparticles is closely linked to the TEOS precursor concentration, while their hydrophobic properties are influenced by the HMDS functionalizing agent. This research work signifies a scalable, cost-effective, and environmentally friendly approach for the fabrication of silica film without using fluorinated compounds.

Metal–semiconductor junctions play a critical role in solar photovoltaic cells by enabling the conversion of light into electrical energy. However, the efficiency of these devices strongly depends on optimizing the M-S interface. This study investigates the performance of the Ag/p-Cu₂BaSnS₄/ ITO heterostructure, focusing on the impact of annealing temperature on its structural, optical, and electrical properties. CBTS thin films were deposited via the sol–gel dip-coating method and subsequently annealed using rapid thermal processing at different temperatures ranging from 673 to 773 K for 10 min. X-ray diffraction revealed a trigonal crystal structure with a pronounced (104) preferred orientation, while Raman spectroscopy confirmed phase purity through a dominant peak at 340 cm⁻¹. Field emission scanning electron microscopy showed a compact morphology with particle size variations influenced by annealing temperature. UV–Vis spectroscopy indicated a redshift in the absorption edge, corresponding to a bandgap reduction from 1.78 to 1.61 eV as the annealing temperature increased. Electrical characterization of the Ag/p-Cu₂BaSnS₄/ITO Schottky diode using current–voltage (I-V) measurements and thermionic emission theory revealed that annealing at 723 K yielded the best performance, with a rectification ratio of 800 and an ideality factor of 5.10. These parameters were further validated using the Cheung method. Impedance spectroscopy confirmed superior charge transport properties for films annealed at 723 K. Overall, the results demonstrate that the Ag/p-Cu₂BaSnS₄/ITO heterostructure holds strong promise for high-efficiency photovoltaic applications, with optimized annealing conditions significantly enhancing device performance.

Seven-light-screen precision target is an new exterior ballistic parameter testing device that enables non-contact measurement of multiple parameters with a single shot, including impact coordinates, flight velocity vector, pitch and azimuth angles of the flight direction, and velocity attenuation rate for obliquely incident flying targets. Precise calibration of structural parameters for invisible light-screen array of seven-light-screen precision target is crucial for ensuring its accuracy and constitutes an essential step in its development. In this paper, we proposes a high-accuracy calibration method. It uses a light-blocking probe to simulate the entry of a projectile into the invisible light screen for the extraction of the actual light screen center. Dual theodolites are employed in conjunction with the readings of a grating ruler during screen crossing to quickly and accurately locate the coordinate points within the screen. Multiple extracted screen coordinate points are then fitted to reconstruct the actual light screen plane, achieving accurate spatial position calibration of multiple invisible screens. This paper introduces the structure and measurement principle of seven-light-screen target, describes the calibration system's composition and working principle, and derives the specific calibration algorithm formulas. The constructed system was applied to calibrate an actual seven-screen target. Live-fire experiments were conducted based on this calibrated target, and the measured impact coordinates were compared against results from cardboard target measurements. The research results show that the structural parameters obtained by the proposed calibration method are accurate. After calibration, the coordinate measurement accuracy of the seven-light-screen precision target within a 1 m × 1 m target sensor area is better than 1.5 mm. This calibration method is universal for the calibration of light-screen arrays with similar principles and provides an effective solution for calibrating structure parameters of multi-light-screen precision targets.

The goal of this investigation is to evaluate the validity of the phenomenological model (PM) for the magnetocaloric effect (MCE) in Ni₂Mn_0.55Cu_0.35Fe_0.10Ga during the first order phase transition (FOPT) at 5 T. Furthermore, the MCE of Ni₂Mn_0.55Cu_0.35Fe_0.10Ga during the second order phase transition (SOPT) is studied. Interestingly, the agreement between the simulated magnetic entropy change (3.5 J/kg.K) and the reported one (3.2 J/kg.K) for FOPT is quite precise across the whole temperature range. Furthermore, Ni₂Mn_0.55Cu_0.35Fe_0.10Ga ‘s relative cooling power has been calculated to be 207 and 73 J/kg for SOPT and FOPT, respectively. Moreover, the simulated heat capacity change via the FOPT reaches a maximum value of 90.8 J/kg.K. These findings suggest that PM is a reliable model for studying MCE in the FOPT and SOPT since it reduces the time and effort necessary to compute and quantify it. Consequently, we believe the PM can be utilized for predicting the MCE parameters in any magnetic transition. It is indicated that Ni₂Mn_0.55Cu_0.35Fe_0.10Ga can be employed as an essential refrigerant magnet at ambient temperature and at higher and lower temperatures.

Coherent Elastic Neutrino-Nucleus Scattering (CE(nu)NS) experiments face significant challenges from background radiation, particularly in above-ground or shallow-overburden environments. Passive shielding, commonly using lead (Pb), is deployed to suppress ambient (gamma)-ray backgrounds. However, such shielding can itself become a source of secondary backgrounds, mainly (gamma) and neutrons, generated by cosmic muon interactions, which can mimic CE(nu)NS signals and degrade experimental sensitivity. In this work, we quantify the rate of these muon-induced secondaries using a high-purity germanium (HPGe) detector in coincidence with plastic scintillator paddles, implementing a time-coincidence technique. The results offer key insights into the nature and rate of Pb-originated cosmogenic backgrounds. The measured mean characteristic time of 11 ± 4 (mu)s for the residual secondary background events agrees well with the Geant4-based Monte Carlo simulation result of 11 ± 1 (mu)s. The measured efficiency-corrected rate of muon-induced events in the HPGe detector is 34 ± 1 (stat.) ± 3 (sys.) (hbox {day}^{-1}) (hbox {kg}^{-1}) within the energy range of 30 keV to 2000 keV. The yield of muon-induced secondary backgrounds in 10-cm-thick Pb shielding is evaluated to be ((11 pm 1 (text { stat.}) pm 1 (text { sys.}))) secondary events(text {kg}^{-1} textrm{m}^{-2} text {muon}^{-1}) at sea level. These findings are essential for the design and background modeling of surface-based CE(nu)NS detectors and have broader relevance for underground experiments and low-threshold detectors used in neutrino, dark matter, and astroparticle physics research.

Crystallization of the prepared transparent 2MgO-2Al₂O₃-3.33B₂O₃ glass system into a well glass-ceramic with optimized crystalline phases that simultaneously improve dielectric properties and lower thermal expansion (CTE) for enhanced functional performance. Despite its chemical equivalence to cordierite stoichiometry (2MgO-2Al₂O₃-5SiO₂), the investigated composition completely substitutes SiO₂ with B₂O₃. The nucleation efficiency of individual (TiO₂, ZrO₂) and combined TiO₂-ZrO₂ additives was rigorously evaluated. The glass-ceramics developed in this work exhibit tailored physicochemical properties (density, hardness, CTE, dielectric properties). Differential thermal analysis (DTA) identified a high crystallization (773–794 °C) for TiO₂-ZrO₂-doped formulations. Phase evolution studies confirmed the crystallization of kotoite (Mg₃B₂O₆), sinhalite (MgAlBO₄), aluminum borate (Al₄B₂O₉), baddeleyite (ZrO₂), and aluminum titanate (Al₂Ti₇O₁₅) at 800–900 °C. The SEM analysis of 900 °C-treated samples revealed a microstructure of submicron rod-like crystallites dispersed in a residual glass phase. Thermo-mechanical characterization yielded CTEs of 12.42–27.55 × 10⁻⁷ °C⁻¹ (25–300 °C) and 22.45–39.19 × 10⁻⁷ °C⁻¹ (25–400 °C). The glass-ceramics (density: 2.54–2.65 g/cm³; hardness: 5.42–5.85 GPa) exhibited superior dielectric properties (high dielectric constant, low dielectric loss) relative to parent glasses (2.61–2.73 g/cm³; 5.11–5.89 GPa), attributable to TiO₂/ZrO₂-derived crystalline phases (Al₂TiO₅, ZrO₂). These attributes combined with low CTE and density suggest viability for microwave substrates or electronic applications.

Motivated by integrating the dilaton field (as a UV correction) with dRGT-like massive gravity (as an IR correction) into Einstein gravity, we investigate the thermodynamic and optical properties of black holes within this gravitational framework. We begin by reviewing the black hole solutions in Maxwell–dilaton–dRGT-like massive gravity, followed by an analysis of how various parameters influence on the asymptotical behavior of the spacetime and the event horizon of these black holes. In the subsequent section, we examine the conserved and thermodynamic quantities associated with these black holes, paying particular attention to the effects of parameters like (beta ,) (alpha ,) and the massive parameters ((eta _{1}) and (eta _{2})) on their local stability by simultaneously evaluating the heat capacity and temperature. We also adopt an alternative method to study phase transitions using geometrothermodynamics. Furthermore, we explore how the parameters of Maxwell–dilaton–dRGT-like massive gravity impacts the optical characteristics and radiative behavior of black holes. In particular, we analyze the effects of the dilaton coupling constant ((alpha ),) charge (q),  the massive gravity parameter ((eta _1),) and the graviton mass ((m_g)) on the radius of the photon sphere and the resulting black hole shadow. Moreover, the theoretical shadow radius is compared to the observational data from (Sgr A^*.) Additionally, we investigate the energy emission rate of these black holes, revealing that these parameters substantially influence the emission peak.

The steady-state quantum dynamics of a compound sample consisting of a semiconductor double quantum dot (DQD) system nonlinearly coupled with a leaking single-mode microresonator is theoretically investigated. The focus is on the resonance condition when the transition frequency of the DQD equals to the doubled resonator frequency, respectively, and the resulting interplay among the involved phonon or photon decay channels. As a result, the steady-state quantum dynamics of this complex nonlinear system exhibits a variety of possible effects that have been demonstrated here. Particularly, we have found the relationship between the electrical current through the double quantum dot and the microwave field inside the resonator, which is nonlinearly coupled to it, with a corresponding emphasis on their critical behaviours. Additionally, the quantum correlations of the photon flux generated into the resonator mode vary from super-Poissonian to Poissonian photon statistics, leading to single-qubit lasing phenomena at microwave frequencies.