BINA

Time lenses can measure ultrafast signals but are based on single-mode fibers (SMFs). To develop multimode time lenses that are based on a four-wave mixing process, we must have full control of the nonlinear interaction between the modes. Specifically, we need to generate an idler from each mode without any cross-talk between the modes. Here, as a first step toward a multimode time lens, we study how stable a short pulse is traveling in a multimode fiber, and how pulses at different modes interact with each other. We utilize a single-mode-based time lens to measure the dynamics of these pulses in the time and spectral domains. We found that there is cross-talk between the modes and that the pulses are not stable and excite other modes, rather than staying in the same modal order. These findings indicate that developing a multimode time-lens may be more challenging than expected.

Method: To elucidate the role of ADAR1 in human islets, we first studied ADAR expression and distribution in human pancreas across postnatal developmental timeline (1 day, 4 months, 2, 6, 10, 35 years). Then we transduced human pseudoislets with a shRNA for ADAR and examined their function and gene expression. The transduced pseudoislets were also transplanted into NSG mice. Insulin secretion was measured and grafts were studied.Results: We found that ADAR1 expression at all ages was greater in endocrine cells than acinar cells. Using the shRNA approach, ADAR mRNA levels were reduced by 70%(n= 11 donors). After 7-day culture, expression of dsRNA sensors, IFNB1, IRF7, IRF9, and interferon-stimulated genes was increased while INS and MAFA expression was reduced in ADAR knockdown islets without changes in insulin secretion. However, 3 weeks post transplantation, glucose/arginine …

Casimir forces, related to London-van der Waals forces, arise if the spectrum of electromagnetic fluctuations is restricted by boundaries. There is great interest both from fundamental science and technical applications to control these forces on the nano scale. Scientifically, the Casimir effect being the only known quantum vacuum effect manifesting between macroscopic objects, allows to investigate the poorly known physics of the vacuum. In this work, we experimentally investigate the influence of self-assembled molecular bio and organic thin films on the Casimir force between a plate and a sphere. We find that molecular thin films, despite being a mere few nanometers thick, reduce the Casimir force by up to 14%. To identify the molecular characteristics leading to this reduction, five different bio-molecular films with varying chemical and physical properties were investigated. Spectroscopic data reveal a broad absorption band whose presence can be attributed to the mixing of electronic states of the underlying gold layer and those of the molecular film due to charge rearrangement in the process of self-assembly. Using Lifshitz theory we calculate that the observed change in the Casimir force is consistent with the appearance of the new absorption band due to the formation of molecular layers. The desired Casimir force reduction can be tuned by stacking several monolayers, using a simple self-assembly technique in a solution. The molecules - each a few nanometers long - can penetrate small cavities and holes, and cover any surface with high efficiency. This process seems compatible with current methods in the production of micro …

Biological structures have evolved to very efficiently generate, transmit, and withstand mechanical forces. These biological examples have inspired mechanical engineers for centuries and led to the development of critical insights and concepts. However, progress in mechanical engineering also raises new questions about biological structures. The past decades have seen the increasing study of failure of engineered structures due to repetitive loading, and its origin in processes such as materials fatigue. Repetitive loading is also experienced by some neurons, for example in the peripheral nervous system. This perspective, after briefly introducing the engineering concept of mechanical fatigue, aims to discuss the potential effects based on our knowledge of cellular responses to mechanical stresses. A particular focus of our discussion are the effects of mechanical stress on axons and their cytoskeletal structures. Furthermore, we highlight the difficulty of imaging these structures and the promise of new microscopy techniques. The identification of repair mechanisms and paradigms underlying long-term stability is an exciting and emerging topic in biology as well as a potential source of inspiration for engineers.

Several decades after the invention of the flow Zn-Br2 systems, persistent attempts have been made to develop stationary Zn-Br2 batteries. Such development should increase the energy density of the system simultaneously significantly reducing their cost and opening new challenges associated with the cell design and its performance. One of the major concerns is the rapid self-discharge of stationary systems leading to spontaneous charge loss during battery storage time. While self-discharge in flow cells is generally attributed to the chemical oxidation of the Zn anode, we show that the origin of self-discharge in a static configuration is completely different. By systematic investigations of activated carbon with different surface areas under varied charging conditions, mechanistic insights into this phenomenon were provided. Based on this understanding, we proposed herein an effective way to suppress the cathode …

Optical properties of chalcogenide topological insulators (TIs), namely, Bi2Se3 (BS) and Bi2Te3 (BT) were studied across the NIR to MIR spectral ranges. In this spectral range, the experimentally measured optical constants revealed an extremely high permittivity values amounting to refractive indices as high as n≈11 and n≈6.4, for BT and BS respectively. These ultra-high index values were then utilized for demonstrating ultracompact, deep-subwavelength nanostructures (NSs), with unit cell sizes down to ~λ/10. Finally, using scattering-type Scanning Near-field Optical Microscopy (s-SNOM), local variations in the optical constants of these nanostructured TIs were studied. Nanoscale phase mapping on a BS NS revealed the role of the imaginary component of the refractive index in the observed phase shifts, varying from as low as ~0.37π to a maximum of ~2π radians across a resonance. This work thus highlights …

Background Chronic peripheral inflammation is well-documented for its ability to alter the activation of the central nervous system (CNS) in diseases such as rheumatoid arthritis (RA) [1]. Furthermore, the CNS is able to regulate inflammatory processes in the periphery [2]. However, the environmental factors facilitating CNS-mediated suppression of peripheral inflammation in RA remain less explored. The intestinal microbiota produces immunomodulatory metabolites, including short-chain fatty acids (SCFA) [3], and neuroactive substances like histamine, which exhibit local and systemic effects [4]. While histamine is commonly associated with allergic reactions, it also possesses immunoregulatory function [5].Objectives Our study aimed to elucidate the impact of gut microbiota-derived histamine on peripheral inflammation.Methods Mice with collagen-induced arthritis (CIA) were orally treated with histamine-producing …

We characterize the spectral response of a silicon chip integrated non-perfect directional coupler by measuring the biphoton joint spectrum at the Hong-Ou-Mandel dip and show the resulting spectral coupling dependency.

A new concept for the sensing of media outside the cladding boundary of standard unmodified fibers will be presented. Light in the single optical mode is used to stimulate mechanical modes of the entire cladding cross-section. The boundary conditions for the oscillations of the mechanical modes are modified by surrounding substances: the outward dissipation of mechanical waves manifests in faster decay rates. The process is monitored through photoelastic scattering of additional optical probe waves. Point-measurements, spatially distributed analysis, and monitoring of coating layers will be presented.

Computational spectrometry is an emerging field that uses photodetection in conjunction with numerical algorithms for spectroscopic measurements. Compact single photodetectors made from layered materials are particularly attractive since they eliminate the need for bulky mechanical and optical components used in traditional spectrometers and can easily be engineered as heterostructures to optimize device performance. However, such photodetectors are typically nonlinear devices, which adds complexity to extracting optical spectra from their response. Here, we train an artificial neural network to recover the full nonlinear spectral photoresponse of a single GeSe-InSe p-n heterojunction device. The device has a spectral range of 400 to 1100 nm, a small footprint of ~25 × 25 square micrometers, and a mean reconstruction error of 2 × 10−4 for the power spectrum at 0.35 nanometers. Using our device, we …

Nanoparticles are widely used in construction. Here, nano-SiO2 is employed, in a way that prevents agglomeration of the nanoparticles, as pozzolanic material to improve Portland cement hydration and to improve the properties of the concrete. To explore the effect of nano-SiO2 and core-shell PS@SiO2 on cement properties, spherical polystyrene particles were prepared by dispersion polymerization of styrene in polar solvents and characterized by FTIR and E-SEM. The core shells PS@SiO2 were synthesized by Stöber method. The results showed an amorphous nano-SiO2 layer can be deposited uniformly on polystyrene particles. This core/shell structure was reducing the aggregation of nano-SiO2 effectively. It was shown that PS@SiO2 particles improved the concrete performances compared to blended cement with nano-SiO2 due to the agglomeration affect. Highlights •Core/shell PS@SiO2 nanoparticles …

Chiral induction of chiral crystals attracts significant attention due to its implications for developing chiral materials and understanding mechanisms of symmetry breaking enantioselective crystallization of naturally chiral inorganic crystals and their potential use in chiral discrimination, which are, however, largely unexplored. Here, we investigate the chiral induction during the crystallization of naturally chiral Ag2CO3 crystals using arginine amino acid as the chiral inducer. The chiral nature of Ag2CO3 was evaluated using various techniques. Chiral crystals exhibited chiral selective binding toward different amino acid enantiomers. The significant selectivity in adsorption was confirmed by circular dichroism, high-performance liquid chromatography, and isothermal titration calorimetry. Understanding chiral induction in crystal growth may open avenues for the controlled assembly of chiral materials and the development …

Leishmania is the causative agent of cutaneous and visceral diseases affecting millions of individuals worldwide. Pseudouridine (Ψ), the most abundant modification on rRNA, changes during the parasite life cycle. Alterations in the level of a specific Ψ in helix 69 (H69) affected ribosome function. To decipher the molecular mechanism of this phenotype, we determine the structure of ribosomes lacking the single Ψ and its parental strain at ∼2.4–3 Å resolution using cryo-EM. Our findings demonstrate the significance of a single Ψ on H69 to its structure and the importance for its interactions with helix 44 and specific tRNAs. Our study suggests that rRNA modification affects translation of mRNAs carrying codon bias due to selective accommodation of tRNAs by the ribosome. Based on the high-resolution structures, we propose a mechanism explaining how the ribosome selects specific tRNAs.

Bacteria use specialized proteins, like transcription factors, to rapidly control metal ion balance. CueR is a Gram‐negative bacterial copper regulator. The structure of E. coli CueR complexed with Cu(I) and DNA was published, since then many studies have shed light on its function. However, P. aeruginosa CueR, which shows high sequence similarity to E. coli CueR, has been less studied. Here, we applied room‐temperature electron paramagnetic resonance (EPR) measurements to explore changes in dynamics of P. aeruginosa CueR in dependency of copper concentrations and interaction with two different DNA promoter regions. We showed that P. aeruginosa CueR is less dynamic than the E. coli CueR protein and exhibits much higher sensitivity to DNA binding as compared to its E. coli CueR homologue. Moreover, a difference in dynamical behavior was observed when P. aeruginosa CueR binds to the …

Layered transition metal dichalcogenides (TMDCs) are considered among the next-generation materials for gas sensing. Here, we report exfoliated 2 H-WS 2 nanosheets for the fabrication of highly performing NO 2 sensors. Thermal annealing at several temperatures was performed to investigate the oxidation of WS 2. The long-term stability of 2 H-WS 2 bulk was verified. Using droplet variation method, three batches of conductometric sensors from 2 H-WS 2 dispersions were fabricated on electrical transducers, namely two layers (2 L), five layers (5 L) and ten layers (10 L) WS 2 nanosheets. These sensors were tested towards low NO 2 concentrations at different temperatures (Room Temperature (20℃), 50℃ and 100℃) and relative humidity (RH) levels (20%, 40%, 60%, 80% and 90% RH). 2 L-WS 2 based sensor showed the highest response at room temperature (RT). Excellent repeatability (4 cycles) towards 1 …

Abstract Hypothesis Room Temperature Ionic Liquids (RTILs) bulk's molecular layering dominates their structure also at the RTIL/sapphire interface, increasing the layer spacing with the cationic alkyl chain length n. However, the negatively-charged sapphire surface compresses the layers, increases the layering range, and affects the intra-layer structure in yet unknown ways. Experiments X-ray reflectivity (XR) off the RTIL/sapphire interface, for a broad homologous RTIL series 1-alkyl-3-methylimidazolium bis (trifluoromethansulfonyl) imide, hitherto unavailable for any RTIL. Findings RTIL layers against the sapphire, exhibit two spacings: d a and d b. d a is n-varying, follows the behavior of the bulk spacing but exhibits a downshift, thus showing significant layer compression, and over twofold polar slab thinning. The latter suggests exclusion of anions from the interfacial region due to the negative sapphire charging …

Magnetic field-induced changes in the electrical resistance of materials reveal insights into the fundamental properties governing their electronic and magnetic behavior. Various classes of magnetoresistance have been realized, including giant, colossal, and extraordinary magnetoresistance, each with distinct physical origins. In recent years, extreme magnetoresistance (XMR) has been observed in topological and non-topological materials displaying a non-saturating magnetoresistance reaching 103−108% in magnetic fields up to 60 T. XMR is often intimately linked to a gapless band structure with steep bands and charge compensation. Here, we show that a linear XMR of 80,000% at 15 T and 2 K emerges at the high-mobility interface between the large band-gap oxides γ-Al2O3 and SrTiO3. Despite the chemically and electronically very dissimilar environment, the temperature/field phase diagrams of γ-Al2O …

Chiral induction of chiral crystals attracts significant attention due to its implications for developing chiral materials and understanding mechanisms of symmetry breaking enantioselective crystallization of naturally chiral inorganic crystals and their potential use in chiral discrimination, which are, however, largely unexplored. Here, we investigate the chiral induction during the crystallization of naturally chiral Ag2CO3 crystals using arginine amino acid as the chiral inducer. The chiral nature of Ag2CO3 was evaluated using various techniques. Chiral crystals exhibited chiral selective binding toward different amino acid enantiomers. The significant selectivity in adsorption was confirmed by circular dichroism, high-performance liquid chromatography, and isothermal titration calorimetry. Understanding chiral induction in crystal growth may open avenues for the controlled assembly of chiral materials and the development …

Insertion of hydrophobic nanoparticles into phospholipid bilayers is limited to small particles that can incorporate into a hydrophobic membrane core between two lipid leaflets. Incorporation of nanoparticles above this size limit requires the development of challenging surface engineering methodologies. In principle, increasing the long-chain lipid component in the lipid mixture should facilitate incorporation of larger nanoparticles. Here, we explore the effect of incorporating very long phospholipids (C24:1) into small unilamellar vesicles on the membrane insertion efficiency of hydrophobic nanoparticles that are 5–11 nm in diameter. To this end, we improve an existing vesicle preparation protocol and utilized cryogenic electron microscopy imaging to examine the mode of interaction and evaluate the insertion efficiency of membrane-inserted nanoparticles. We also perform classical coarse-grained molecular …

Nickel-rich layered oxide cathode materials with low cobalt content, such as LiNi 0.90 Mn 0.05 Co 0.05 O 2 (NMC90), have the potential to enable cost-effective, high-energy-density lithium-metal batteries. However, NMC90 cathode materials are prone to severe parasitic reactions at higher voltages during prolonged cycling. The addition of small percentages of electrolyte additives to the neat commercial electrolyte can significantly enhance the overall electrochemical performance of lithium-metal batteries. This study investigates the effects of zinc triflate (Zn (Otf) 2) as an electrolyte additive on the enhancement of the electrochemical performances of lithium-metal batteries comprising nickel-rich layered oxide cathode materials. X-ray photoelectron spectroscopy analysis revealed that Zn (Otf) 2 decomposition leads to enhanced fluorination at the interfacial layers, which contributes to improved chemical stability …