BINA

Base editors are engineered deaminases combined with CRISPR components. These engineered deaminases are designed to target specific sites within DNA or RNA to make a precise change in the molecule. In therapeutics, they hold promise for correcting mutations associated with genetic diseases. However, a key challenge is minimizing unintended edits at off-target sites, which could lead to harmful mutations. Researchers are actively addressing this concern through a variety of optimization efforts that aim to improve the precision of base editors and minimize off-target activity. Here, we examine the various types of off-target activity, and the methods used to evaluate them. Current methods for finding off-target activity focus on identifying similar sequences in the genome or in the transcriptome, assuming the guide RNA misdirects the editor. The main method presented here, that was originally developed to …

The study of first passage times for diffusing particles reaching target states is foundational in various practical applications, including diffusion-controlled reactions. In this work, we present a bi-scaling theory for the probability density function of first passage times in confined compact processes, applicable to both Euclidean and Fractal domains, diverse geometries, and scenarios with or without external force fields, accommodating Markovian and semi-Markovian random walks. In large systems, first passage time statistics exhibit a bi-scaling behavior, challenging the use of a single time scale. Our theory employs two distinct scaling functions: one for short times, capturing initial dynamics in unbounded systems, and the other for long times is sensitive to finite size effects. The combined framework provides a complete expression for first passage time statistics across all time scales.

We generalize the scope of Floquet engineering to include spatially-dependent modulations of an optical system. As an application, we show that we can transform large classes of Hamiltonians into one another by driving them in a time-periodic but spatially non-uniform manner. We propose several experimental realizations in 1D optical lattices, including freeing disordered lattices from Anderson localization, as well as effectively disconnecting all their sites. These techniques straightforwardly extend to more complex classes of systems.

Mathematical models of voltammetric experiments commonly contain a singular point value for the reversible potential, whereas experimental data for surface-confined redox-active species is often interpreted to contain thermodynamic dispersion, meaning the population of molecules on the electrode possess a distribution of reversible potential values. Large amplitude ramped Fourier Transformed Alternating Current Voltammetry (FTacV), a technique in which a sinusoidal potential-time oscillation is overlaid onto a linear potential-time ramp, is known to provide access to higher order harmonic components that are largely devoid of non-Faradaic current. Initially, a theoretical study reveals that the use of very large amplitude sinusoidal oscillations reduces the apparent effects of thermodynamic dispersion; conversely, frequency can be varied to change the sensitivity of the measurement to kinetic dispersion. Subsequently, FTacV measurements are used to probe a highly thermodynamically dispersed surface-confined ferrocene derivative attached to a glassy carbon electrode, with amplitudes ranging from 25 to 300 mV and low frequency, which minimises the impact of kinetic dispersion. The results from the experimental study validate the theoretical predictions, demonstrating that we can vary the amplitude in FTacV experiments to tune in and out of thermodynamic dispersion.

In this work, we elucidate the crucial role of borate anions ([B(OH)4]-) for the electrocatalytic urea oxidation reaction (UOR) using a nanoporous metallic nickel (NP-Ni) catalyst grown on Si substrates. The UOR activity of the NP-Ni catalyst has been studied at various boric acid (H3BO3) concentrations, demonstrating superior activity at a specific electrolytic composition of 0.5 M KOH, 0.33 M urea, and 50 mM of H3BO3. Based on a wide range of electrochemical techniques, such as, cyclic voltammetry (CV), linear sweep voltammetry (LSV), Pb-anodic deposition, and chronoamperometry (CA), we develop a potential mechanism for the [B(OH)4]--mediated UOR. The high double layer capacitance, surface density of Ni redox sites, and urea oxidation currents, clearly demonstrate the significant impact of [B(OH)4]- during electrolysis. Furthermore, we find that UOR catalyzed by the NP-Ni is controlled by diffusion both in presence and absence of [B(OH)4]-. Finally, a set of physical characterizations, including XPS, SEM, and TEM were performed to correlate the composition and structure of the NP-Ni to the [B(OH)4]--mediated increased UOR activity. The boosted UOR we obtain can open new avenues for treatment of wastewater and assist with environmental remediation.

Classical and wave properties of pseudosphere-shape microlasers are investigated through experiments and numerical simulations. These pseudosphere microlasers are surface-like organic microlasers with constant negative curvature, which were fabricated with high optical quality by direct laser writing. It is shown that they behave, in many ways, similar to two-dimensional flat disks, regardless of the different Gaussian curvature of the two systems. Indeed, it is evidenced that, due to rotational symmetry, the pseudosphere is an integrable system with marginally stable dynamics.

Rechargeable Zn-air batteries with near-neutral electrolytes hold promise as cheap, safe and sustainable devices, but they suffer from slow charge kinetics and remain poorly studied. Here we reveal a charge storage mechanism of near-neutral Zn-air batteries that is mediated by H2O2 formation upon cell discharge and its oxidation upon charge. The manifestation of this mechanism strongly depends on the electrolyte composition and positive electrode material, being pronounced when ZnSO4 solutions and carbon nanotubes are employed. Oxidation of dissolved H2O2 is facile, enabling oxygen evolution reaction (OER) at low potentials (~1.5 V vs. Zn2+/Zn) which, in contrast to conventional four-electron OER, does not induce corrosion of carbon electrodes. Facilitation of the H2O2-mediated pathway might therefore be helpful for developing high-performance near-neutral Zn-air batteries.

Temporal optics rises from the equivalence between light diffraction in free space and pulse dispersion in dispersive media, paving the way for the development of temporal devices and applications, such as time-lenses. A Four-wave mixing based time-lens allows single-shot measurements of ultra-short signals in high temporal resolution by imaging signals, and inducing temporal Fourier transform. We introduce a cascade time-lens by utilizing a cascade FWM process within the time-lens. We theoretically develop and experimentally demonstrate the cascade time-lens, and confirm that different cascade orders correspond to different effective temporal systems, leading to measuring in various temporal imaging configurations simultaneously with a single optical setup. This approach can simplify experiments and provide a more comprehensive view of a signal’s phase and temporal structure. Such capabilities are …

The intrinsic sluggishness of oxygen reduction reaction (ORR) limits the widespread adoption of low-temperature anion exchange membrane fuel cells (AEMFCs) technology, and effective ORR electrocatalysts and methods for ORR enhancement are needed. Herein, we investigate the mechanism behind the improvement of ORR activity of Ag electrocatalyst coated with a shell based on polydopamine (PDA) crosslinked with polyethylene imine (PEI) during AEMFC operation. We show a correlation between electrochemical and physical properties of the PDA/PEI Ag catalyst, with its performance within membrane-electrode assembly (MEA) in practical fuel cell operating environments. Higher current density observed in a catalytic region of polarization curve in AEMFC, matches the positive shift in the half-wave potential of ORR on Ag PDA/PEI as measured by rotating disc electrode (RDE) experiments. Additionally …

We investigate a system of Brownian particles weakly bound by attractive parity-symmetric potentials that grow at large distances as , with . The probability density function at long times reaches the Boltzmann-Gibbs equilibrium state, with all moments finite. However, the system's relaxation is not exponential, as is usual for a confining system with a well-defined equilibrium, but instead follows a stretched exponential with exponent . This problem is studied from three perspectives. First, we propose a straightforward and general scaling rate-function solution for . This rate-function, which is an important tool from large deviation theory, also displays anomalous time scaling and a dynamical phase transition. Second, through the eigenfunctions of the Fokker-Planck operator, we obtain, using the WKB method, more complete solutions that reproduce the rate function approach. Finally, we show how the alternative path-integral formalism allows us to recover the same results, with the above rate-function being the solution of the classical Hamilton-Jacobi equation describing the most probable path. Properties such as parity, the role of initial conditions, and the dynamical phase transition are thoroughly studied in all three approaches.

Background and objective Methods Key findings and limitations

Triggered by the development of exfoliation and the identification of a wide range of extraordinary physical properties in self-standing films consisting of one or few atomic layers, two-dimensional (2D) materials such as graphene, transition metal dichalcogenides (TMDs), and other van der Waals (vdW) crystals currently constitute a wide research field protruding in multiple directions in combination with layer stacking and twisting, nanofabrication, surface-science methods, and integration into nanostructured environments. Photonics encompasses a multidisciplinary collection of those directions, where 2D materials contribute with polaritons of unique characteristics such as strong spatial confinement, large optical-field enhancement, long lifetimes, high sensitivity to external stimuli (e.g., electric and magnetic fields, heating, and strain), a broad spectral range from the far infrared to the ultraviolet, and hybridization with spin and momentum textures of electronic band structures. The explosion of photonics with 2D materials as a vibrant research area is producing breakthroughs, including the discovery and design of new materials and metasurfaces with unprecedented properties as well as applications in integrated photonics, light emission, optical sensing, and exciting prospects for applications in quantum information, and nanoscale thermal transport. This Roadmap summarizes the state of the art in the field, identifies challenges and opportunities, and discusses future goals and how to meet them through a wide collection of topical sections prepared by leading practitioners.

Understanding oscillatory behavior in human networks is essential for exploring synchronization, coordination, and collective dynamics. In this study, we investigate tempo oscillations in complex human networks using a system of coupled violin players with precisely controlled network parameters. Each player interacts via delayed auditory feedback, allowing us to explore the effects of connectivity, delay, and tempo on network oscillations. We identify two distinct types of oscillations: fast (2–3 seconds) and slow (5–15 seconds), and demonstrate that their periods are independent of network size and delay but are strongly correlated with the network's average tempo. Additionally, we show that increasing the number of coupled neighbors enhances oscillation damping, indicating the role of connectivity in stabilizing network dynamics. By varying the delay rate, we discover a critical decay rate where oscillation …