BINA

The spectra of Brillouin scattering processes in optical fibers are affected by temperature, axial strain, and other quantities of interest. This dependence forms the basis for optical Brillouin scattering based optical fiber sensors. Since the first proposition of such sensors in 1989, several protocols have been established for the spatially distributed analysis of Brillouin scattering spectra along fibers installed in structures of interest. Sensor systems cover hundreds of kilometers, reach sub-millimeter resolution, follow dynamic vibrations at MHz rates, and resolve sub-degree temperature changes and micro-strain elongations. Optical fiber sensors represent the most successful commercial application of Brillouin scattering physics to-date. This chapter reviews the principles, state of the art, performance trade-offs and recent breakthroughs in Brillouin scattering-based optical fiber sensors.

Doped Mott insulators exhibit some of the most intriguing quantum phases of matter, including quantum spin-liquids, unconventional superconductors, and non-Fermi liquid metals. Such phases often arise when itinerant electrons are close to a Mott insulating state, and thus experience strong spatial correlations. Proximity between different layers of van der Waals heterostructures naturally realizes a platform for experimentally studying the relationship between localized, correlated electrons and itinerant electrons. Here, we explore this relationship by studying the magnetic landscape of 4Hb-TaS2, which realizes an alternate stack of a candidate spin liquid and a superconductor. We report on a spontaneous vortex phase whose vortex density can be trained in the normal state. We show that time reversal symmetry is broken above Tc, indicating the presence of a magnetic phase independent of the superconductor. Strikingly, this phase does not generate detectable magnetic signals. We use scanning superconducting quantum interference device (SQUID) microscopy to show that it is incompatible with ferromagnetic ordering. The discovery of this new form of hidden magnetism illustrates how combining superconductivity with a strongly correlated system can lead to new, unexpected physics.

Magnetic hydrogels and soft composites have fuelled the development of next generation biomimetic soft robotics due to their precise control and non-cytotoxic nature. Bare magnetic nanoparticles are difficult to regulate via remote controlling whereas, when these nanoparticles are arrested inside polymeric matrices, the whole system become an artificial soft mussel like integrated system. Concurrently, these polymeric magnetic soft materials are also prone to response of external magnetic field (static or oscillatory). Additive manufacturing via spatial assembly of polymeric precursors followed by actuation like behaviour is quite a new manufacturing technique to fabricate magnetic soft materials. In this review, we focused on the magnetic nanoparticles and their entrapment into polymeric matrices and assessing their applicability in clinical (hyperthermia) as well as shape morphing behaviours. Both the behaviors …

Uncertainty relations play a crucial role in quantum mechanics. A well-defined method exists for deriving such uncertainties for pairs of observables. It does not include, however, an important family of fundamental relations: the time-energy uncertainty relations. As a result, different approaches have been used for obtaining them in diversified scenarios. The one of interest here revolves around the idea of the existence or inexistence of a minimum duration for an energy measurement with a certain precision. In our study, we use the Page and Wooters timeless framework to investigate how energy measurements modify the relative "flow of time" between internal and external clocks. This provides a unified framework for discussing the topic, recovering previous results and leading to new ones. We also show that the evolution of the external clock with respect to the internal one is non-unitary.

Lysozyme is widely known to promote the formation of condensed silica networks from solutions containing silicic acid, in a reproducible and cost-effective way. However, little is known about the fate of the protein after the formation of the silica particles. Also, the relative arrangement of the different components in the resulting material is a matter of debate. In this study, we investigate the nature of the protein–silica interactions by means of solid-state nuclear magnetic resonance spectroscopy, small-angle X-ray scattering, and electron microscopy. We find that lysozyme and silica are in intimate contact and strongly interacting, but their interaction is neither covalent nor electrostatic: lysozyme is mostly trapped inside the silica by steric effects.

Magnesium ion (Mg2+) is one of the most significant cations in living systems with involvement in many biochemical reactions and cellular processes and hence, sensitive and specific detection of Mg2+ is therefore essential for various applications. Here, we report the solvothermal synthesis of boron‐doped carbon dots (BC10) with more oxygen surface states by using salicylaldehyde and naphthalene‐1‐boronic acid. The as‐prepared BC10 showed greenish‐white luminescence under 365 nm UV illumination with quantum yield (QY) of 5.5 % at optimum dilution with dimethyl sulfur oxide (DMSO) solvent. The BC10 in DMSO (DS‐BC10) have shown high selectivity and sensitivity towards Mg2+ ion through the increased PL intensity due to chelation‐enhanced photoluminescence (CHEP). The enhanced PL intensity was further supported by the increased QY by a factor of 12 after the addition of Mg2+ ions to 65 …

We present our current understanding of various aspects of Efimov physics originating from the complex multichannel hyperfine structure and overlap of Feshbach resonances for 7Li atoms. This further help us to explain puzzling experimental observations with ultracold gases. We have characterized the energies of Efimov states and corresponding interference and resonance scattering phenomena associated to them as a function of an external magnetic field. Our results also indicate that Efimov states in the 7Li system can have a unique mixed hyperfine character which strongly affect their near-threshold behavior for repulsive interatomic interactions.[1] Y. Yudkin, R. Elbaz, L. Khaykovich, arXiv: 2004.02723.

Trypanosoma brucei, the parasite that causes sleeping sickness, cycles between an insect and a mammalian host. However, the effect of RNA modifications such as pseudouridinylation on its ability to survive in these two different host environments is unclear. Here, two genome-wide approaches were applied for mapping pseudouridinylation sites (Ψs) on small nucleolar RNA (snoRNA), 7SL RNA, vtRNA, and tRNAs from T. brucei. We show using HydraPsiSeq and RiboMeth-seq, that the Ψ on C/D snoRNA guiding 2’-O-methylation increased the efficiency of the guided modification on its target, rRNA. We found differential levels of Ψs on these ncRNAs in the two life stages (insect host and mammalian host) of the parasite. Furthermore, tRNA isoform abundance and Ψ modifications were characterized in these two life stages demonstrating stage-specific regulation. We conclude that the differential Ψ modifications …

Super-resolution optical fluctuation imaging (SOFI) is a highly democratizable technique that provides optical super-resolution without requirement of sophisticated imaging instruments. Easy-to-use open-source packages for SOFI are important to support the utilization and community adoption of the SOFI method, they also encourage the participation and further development of SOFI by new investigators. In this work, we developed PySOFI, an open-source Python package for SOFI analysis that offers the flexibility to inspect, test, modify, improve, and extend the algorithm. We provide complete documentation for the package and a collection of Jupyter Notebooks to demonstrate the usage of the package. We discuss the architecture of PySOFI and illustrate how to use each functional module. A demonstration on how to extend the PySOFI package with additional modules is also included in the PySOFI package. We …

Purpose: Stem cells replacement therapy is becoming a promising pursued avenue for vision restoration in people with degenerative diseases of the outer retina. However, the integration and survival of the transplanted cells and the formation of fully functioning synapses remain a challenge. Our aim is to develop an in-vitro experimental paradigm which will allow us to address these issues while working under experimentally controlled conditions and avoiding immune system reactions faced in-vivoMethods: As a first step, we are utilizing organotypic retinal cultures from transgenic rats expressing the calcium indicator GCaMP6f while monitoring the survival of the retinal ganglion cells (RGCs) using both extracellular recordings (multi electrode arrays), and calcium imaging at various time points.Results: Our calcium imaging revealed robust spontaneous activity of the RGCs up to 72hrs, albeit decreasing throughout …

We present our current understanding of various aspects of Efimov physics originating from the complex multichannel hyperfine structure and overlap of Feshbach resonances for 7Li atoms. This further help us to explain puzzling experimental observations with ultracold gases. We have characterized the energies of Efimov states and corresponding interference and resonance scattering phenomena associated to them as a function of an external magnetic field. Our results also indicate that Efimov states in the 7Li system can have a unique mixed hyperfine character which strongly affect their near-threshold behavior for repulsive interatomic interactions.[1] Y. Yudkin, R. Elbaz, L. Khaykovich, arXiv: 2004.02723.

The need for high power density cathodes for Li‐ion batteries can be fulfilled by application of a high charging voltage above 4.5 V. As lithium cobalt oxide (LCO) remains a dominant commercial cathode material, tremendous efforts are invested to increase its charging potential toward 4.6 V. Yet, the long‐term performance of high voltage LCO cathodes still remains poor. Here, an integrated approach combining the application of an aluminum fluoride coating and the use of electrolyte solutions comprising 1:1:8 mixtures of difluoroethylene:fluoroethylene carbonate:dimethyl carbonate and 1 m LiPF6 is reported. This results in superior behavior of LCO cathodes charged at 4.6 V with high initial capacity of 223 mAh g−1, excellent long‐term performance, and 78% capacity retention after 500 cycles. Impressive stability is also found at 450 °C with an initial capacity of 220 mAh g−1 and around 84% capacity retention …

Background Inflammatory myopathies (IM) are a heterogeneous group of disorders characterized by autoimmune inflammatory destruction of skeletal muscles. It is many times associated with lung, skin and joint involvement. Identifying biomarkers that can differentiate IM from other muscle disorders may elucidate the pathophysiology of IM, guide novel therapies, monitor disease activity/response to treatments and predict prognosis. Exosomes are membrane-bound nanovesicles with diameters of 30-150 nm that contain multiple proteins, nucleic acid, lipids and other molecules in a tissue- and cell-specific manner. Exosomes are secreted by a large variety of cells, play major roles in cell-cell interactions, and have recently emerged as circulating biomarkers in a variety of pathological conditions, including several autoimmune diseases.Objectives To characterize exosomes from serum of IM patients, analyze protein …

The two-dimensional electron system found between LaAlO3 and SrTiO3 hosts a variety of physical phenomena that can be tuned through external stimuli. This allows for electronic devices controlling magnetism, spin–orbit coupling, and superconductivity. Controlling the electron density by varying donor concentrations and using electrostatic gating are convenient handles to modify the electronic properties, but the impact on the microscopic scale, particularly of the former, remains underexplored. Here, we image the current distribution at 4.2 K in amorphous-LaAlO3/SrTiO3 using scanning superconducting quantum interference device microscopy while changing the carrier density in situ using electrostatic gating and oxygen annealing. We show how potential disorder affects the current and how homogeneous 2D flow evolves into several parallel conducting channels when approaching the metal-to-insulator …

The pathogen Bordetella pertussis uses a type-3 secretion system (T3SS) to inject its cytotoxic effector BteA into the host cell via a designated needle structure. Prior to injection BteA is bound to its cognate chaperone BtcA presumed to assist in effector unfolding en route to needle passage. We utilized NMR and EPR spectroscopy to uncover the molecular mechanism of BtcA-mediated unfolding of BteA. BtcA induces a global structural change in the effector, which adopts a more extended and partially unfolded conformation. EPR distance measurements further show that the structured helical-bundle form of free BteA exists in conformational equilibrium with a lowly populated minor species. The nature of this equilibrium was probed using NMR relaxation dispersion experiments. At 283 K structural effects are most pronounced for a contiguous surface spanning the A- and B-helices of BteA, extending at 303 K to a …

High-performance electrolytes are at the heart of magnesium battery development. Long-term stability along with the low potential difference between plating and stripping processes are needed to consider them for next-generation battery devices. Within this work, we perform an in-depth characterization of the novel Mg[Al(hfip)4]2 salt in different glyme-based electrolytes. Specific importance is given to the influence of water content and the role of additives in the electrolyte. Mg[Al(hfip)4]2-based electrolytes exemplify high tolerance to water presence and the beneficial effect of additives under aggravated cycling conditions. Finally, electrolyte compatibility is tested with three different types of Mg cathodes, spanning different types of electrochemical mechanisms (Chevrel phase, organic cathode, sulfur). Benchmarking with an electrolyte containing a state-of-the-art Mg[B(hfip)4]2 salt exemplifies an improved …

The future of Halide Perovskites, HaPs, which are of enormous interest for light ⟷ electrical energy conversion, is beclouded by limited scientific understanding of their long‐term stability. While HaPs can be altered by absorbed radiation that induces multiple processes, remarkably, they can also return to their original state by “self‐healing”. Here we use 2‐photon absorption to effect light‐induced modifications within single crystals of MAPbI3, the prototypical HaP. We then follow the changes in the photo‐damaged region by measuring the photoluminescence, resulting also from 2‐photon absorption, but with 2.5 orders of magnitude lower intensity than that used for photodamaging the MAPbI3. We find, immediately after photo‐damage, two brightening and one darkening process, all of which recover but on different timescales. The first two are attributed to trap‐filling (the fastest) and to proton‐amine related …

Dissipative solitons are fundamental wave-pulses that preserve their form in the presence of periodic loss and gain. The canonical realization of dissipative solitons is Kerr-lens mode locking (KLM) in lasers, which delicately balance nonlinear and linear propagation in both time and space to generate ultrashort optical pulses. This linear-nonlinear balance dictates a unique pulse energy, which cannot be increased (say by elevated pumping), indicating that excess energy is expected to be radiated in the form of dispersive or diffractive waves. Here we show that KLM lasers can overcome this expectation. Specifically, by breaking the spatial symmetry between the forward and backward halves of the round-trip in a linear cavity, the laser can modify the soliton in space to incorporate the excess energy. Increasing the pump power leads therefore to a different soliton solution, rather than to dispersive/diffractive loss. We predict the symmetry breaking by a complete numerical simulation of the spatio-temporal dynamics in the cavity, and confirm it experimentally in a KLM Ti: Sapphire laser with quantitative agreement to the simulation. The simulation opens a window to directly observe the nonlinear space-time dynamics that molds the soliton pulse, and possibly to optimize it.