BINA

Functional polymers are increasingly recognized for their ability to engineer the electronic properties of 2D materials for device performance enhancement. Although dipole-rich polymer zwitterions have shown significant work function modulation of 2D materials, the contribution of zwitterion structure is not well understood. To this end, a series of zwitterionic sulfobetaine-based random copolymers with varying substituents has been prepared and applied as negative-tone resists on graphene, enabling evaluation of surface potential contrast. The influence of steric footprint on calculated dipole moment and resulting work function measured by ultraviolet photoelectron spectroscopy will be presented. To assess the nature of graphene surface doping by polymer zwitterions, a sample geometry that permits direct access to either the polymer or graphene side is employed using a zwitterionic phosphorylcholine-based …

We study the aberrations of four-wave mixing-based time-lenses resulting from the cross-phase modulations of the pump wave. These temporal aberrations have no spatial equivalent and are important when imaging weak signals with strong pump waves.In this work we show that as the pump power increases the cross-phase modulations of the pump are responsible for shifting, defocusing, and imposing temporal coma aberrations on the image.

The superconducting transition temperature (Tc) of a single layer graphene coupled to an Indium oxide (InO) film, a low carrier-density superconductor, is found to increase with decreasing carrier density and is largest close to the average charge neutrality point in graphene. Such an effect is very surprising in conventional BCS superconductors. We study this phenomenon both experimentally and theoretically. Our analysis suggests that the InO film induces random electron and hole-doped puddles in the graphene. The Josephson effect across these regions of opposite polarity enhances the Josephson coupling between the superconducting clusters in InO, along with the overall Tc of the bilayer heterostructure. This enhancement is most effective when the chemical potential of the system is tuned between the charge neutrality points of the electron and hole-doped regions.

The intercalation of layered compounds is a promising route for scalable synthesis of 2D heterostructures with novel emergent optoelectronic properties. Here, we investigate, via first principles calculations, the intercalation of zerovalent metals within the van der Waals gap of bulk MoS 2. Specifically, we focus on a novel Cu-MoS 2 hybrid that accommodates uniform, continuous 2D layers of metallic Cu within the vdW gap of MoS 2. We study the evolution of the Cu-MoS 2 hybrid with increasing Cu content and examine the consequences for intercalation energetics and optoelectronic properties as the intercalated Cu evolves from disordered clusters to contiguous layers. We identify an emergent plasmon resonance (~ 1eV) that is unique to the Cu-MoS 2 hybrid, arising from resonant 2D Cu states within the MoS 2 band gap. Our calculations are shown to be in good agreement with experiments and help explain the …

We present a study of various compositions of the chalcogenide family used for static and active metasurfaces. We start with large area CVD grown amorphous spherical Selenium nanoparticles on various substrates and show that their Mie-resonant response spans the entire mid-infrared (MIR) range. By coupling Se Mie-resonators to ENZ substrates we demonstrate an order of magnitude increase in quality factor. Next, we investigate topological insulators Bi2Se3 and Bi2Te3 metasurfaces. We study the optical constants of single crystal Bi2Te3 in the NIR to the MIR range, followed by fabrication and characterization of metasurface disk arrays. We show that these high permittivity metasurfaces can yield very large absorption resonances using deep subwavelength structures. Finally, we demonstrate ultra-wide dynamic tuning of PbTe meta-atoms and metasurfaces, utilizing the anomalously large thermo-optic …

The protozoan parasite Leishmania donovani causes fatal human visceral leishmaniasis in absence of treatment. Genome instability has been recognized as a driver in Leishmania fitness gain in response to environmental change or chemotherapy. How genome instability generates beneficial phenotypes despite potential deleterious gene dosage effects is unknown. Here we address this important open question applying experimental evolution and integrative systems approaches on parasites adapting to in vitro culture. Phenotypic analyses of parasites from early and late stages of culture adaptation revealed an important fitness tradeoff, with selection for accelerated growth in promastigote culture (fitness gain) impairing infectivity (fitness costs). Comparative genomics, transcriptomics and proteomics analyses revealed a complex regulatory network associated with parasite fitness gain, with genome instability causing highly reproducible, gene dosage-independent and -dependent changes. Reduction of flagellar transcripts and increase in coding and non-coding RNAs implicated in ribosomal biogenesis and protein translation were not correlated to dosage changes of the corresponding genes, revealing a gene dosage-independent, post-transcriptional mechanism of regulation. In contrast, abundance of gene products implicated in post-transcriptional regulation itself correlated to corresponding gene dosage changes. Thus, RNA abundance during parasite adaptation is controled by direct and indirect gene dosage changes. We correlated differential expression of small nucleolar RNAs (snoRNAs) with changes in rRNA modification …

The superconducting transition temperature (Tc) of a single layer graphene coupled to an Indium oxide (InO) film, a low carrier-density superconductor, is found to increase with decreasing carrier density and is largest close to the average charge neutrality point in graphene. Such an effect is very surprising in conventional BCS superconductors. We study this phenomenon both experimentally and theoretically. Our analysis suggests that the InO film induces random electron and hole-doped puddles in the graphene. The Josephson effect across these regions of opposite polarity enhances the Josephson coupling between the superconducting clusters in InO, along with the overall Tc of the bilayer heterostructure. This enhancement is most effective when the chemical potential of the system is tuned between the charge neutrality points of the electron and hole-doped regions.

This study aims to investigate the effects of a novel ZnCuO nanoparticle coating for dental implants—versus those of conventional titanium surfaces—on bacteria and host cells. A multispecies biofilm composed of Streptococcus sanguinis, Actinomyces naeslundii, Porphyromonas gingivalis, and Fusobacterium nucleatum was grown for 14 days on various titanium discs: machined, sandblasted, sandblasted and acid-etched (SLA), ZnCuO-coated, and hydroxyapatite discs. Bacterial species were quantified with qPCR, and their viability was examined via confocal microscopy. Osteoblast-like and macrophage-like cells grown on the various discs for 48 h were examined for proliferation using an XTT assay, and for activity using ALP and TNF-α assays. The CSLM revealed more dead bacteria in biofilms grown on titanium than on hydroxyapatite, and less on sandblasted than on machined and ZnCuO-coated surfaces, with the latter showing a significant decrease in all four biofilm species. The osteoblast-like cells showed increased proliferation on all of the titanium surfaces, with higher activity on the ZnCuO-coated and sandblasted discs. The macrophage-like cells showed higher proliferation on the hydroxyapatite and sandblasted discs, and lower activity on the SLA and ZnCuO-coated discs. The ZnCuO-coated titanium has anti-biofilm characteristics with desired effects on host cells, thus representing a promising candidate in the complex battle against peri-implantitis.

RNA editing by adenosine deaminases changes the information encoded in the mRNA from its genomic blueprint. Editing of protein-coding sequences can introduce novel, functionally distinct, protein isoforms and diversify the proteome. The functional importance of a few recoding sites has been appreciated for decades. However, systematic methods to uncover these sites perform poorly, and the full repertoire of recoding in human and other mammals is unknown. Here we present a new detection approach, and analyze 9125 GTEx RNA-seq samples, to produce a highly-accurate atlas of 1517 editing sites within the coding region and their editing levels across human tissues. Single-cell RNA-seq data shows protein recoding contributes to the variability across cell subpopulations. Most highly edited sites are evolutionary conserved in non-primate mammals, attesting for adaptation. This comprehensive set can …

Topological insulators (TIs) are a new class of condensed matter system that host topologically protected surface states, leading to dissipationless electron transport. This intrinsic characteristic makes them potential candidate for quantum computing owing to their ability to preserve quantum coherence. Recently, these systems and the concept of topology have been embraced by the photonics community as well. In this work, we study the mid-infrared optical properties of high index (n~5.2) TI bismuth selenide (Bi2Se3) nanobeams (NBs), grown by chemical vapor deposition. Using Finite-difference time-domain (FDTD) simulations and FTIR nanospectroscopy, we find that these NBs support size-tunable Mie-resonant modes across the infrared (~1-16 µm). Furthermore, polarized measurements reveal that the total optical response of these deep subwavelength NBs is composed of TE and TM resonant mode. Finally …

We present a study of various compositions of the chalcogenide family used for static and active metasurfaces. We start with large area CVD grown amorphous spherical Selenium nanoparticles on various substrates and show that their Mie-resonant response spans the entire mid-infrared (MIR) range. By coupling Se Mie-resonators to ENZ substrates we demonstrate an order of magnitude increase in quality factor. Next, we investigate topological insulators Bi2Se3 and Bi2Te3 metasurfaces. We study the optical constants of single crystal Bi2Te3 in the NIR to the MIR range, followed by fabrication and characterization of metasurface disk arrays. We show that these high permittivity metasurfaces can yield very large absorption resonances using deep subwavelength structures. Finally, we demonstrate ultra-wide dynamic tuning of PbTe meta-atoms and metasurfaces, utilizing the anomalously large thermo-optic …

Efficient light manipulation at subwavelength scales in the mid-infrared (MIR) region is essential for various applications and can be harnessed from intrinsic low-loss dielectric resonators. Here, we demonstrate the fabrication of truncated spherical selenium (Se) resonators with tunable high-quality (Q) factor Mie resonances. Large area amorphous Se subwavelength resonators of varying sizes were grown on different substrates, using a novel CVD process. We demonstrate size-tunable Mie resonances spanning the 2-16 µm range, for single isolated resonators and large area ensembles, respectively. We show strong tunable absorption resonances (90%) in ensembles of resonators in a significantly broad MIR range. Moreover, by coupling resonators to epsilon-near-zero (ENZ) substrates, we engineer high-Q resonances as high as Q=40. We also show the resonance pinning effect near the substrate ENZ value …

Behavioral neuroscience underwent a technology-driven revolution with the emergence of machine-vision and machine-learning technologies. These technological advances facilitated the generation of high-resolution, high-throughput capture and analysis of complex behaviors. Therefore, behavioral neuroscience is becoming a data-rich field. While behavioral researchers use advanced computational tools to analyze the resulting datasets, the search for robust and standardized analysis tools is still ongoing. At the same time, the field of genomics exploded with a plethora of technologies which enabled the generation of massive datasets. This growth of genomics data drove the emergence of powerful computational approaches to analyze these data. Here, we discuss the composition of a large behavioral dataset, and the differences and similarities between behavioral and genomics data. We then give examples of genomics-related tools that might be of use for behavioral analysis and discuss concepts that might emerge when considering the two fields together.

Interferometers are highly sensitive to phase differences and are utilized in numerous schemes. Quantum interferometers are able to improve the sensitivity of classical interferometers beyond the shot-noise limit. This is done by employing squeezed states of light and destructive interference of the noise in the system. We developed a quantum SU(1,1) interferometer in the time domain. Our nonlinear quantum interferometer creates interference of the input signals at different times and frequencies. We can control the time and frequency differences for investigating the full temporal and spectral structure of the signal. This quantum interferometer can be utilized for sensing ultrafast phase changes, quantum imaging, temporal mode encoding, and studying the temporal structure of entangled photons.

Near-Infrared wide-field Fluorescence Lifetime Imaging (FLI) has become an increasingly popular method due to its unique specificity in sensing the cellular micro-environment and/or protein-protein interactions via FRET, but the approach is still challenging due to inefficient detection modules. Here, we report on the characterization of a large gated SPAD array, SwissSPAD2, towards in vivo preclinical imaging of FLI-FRET. Fluorescence decay fitting as well as phasor analysis are used to demonstrate the ability of SwissSPAD2 to accurately quantify short lifetimes and associated lifetime parameters in both in vitro and in vivo experiments, in full agreement with gated ICCD measurements.

Efficient light manipulation at subwavelength scales in the mid-infrared (MIR) region is essential for various applications and can be harnessed from intrinsic low-loss dielectric resonators. Here, we demonstrate the fabrication of truncated spherical selenium (Se) resonators with tunable high-quality (Q) factor Mie resonances. Large area amorphous Se subwavelength resonators of varying sizes were grown on different substrates, using a novel CVD process. We demonstrate size-tunable Mie resonances spanning the 2-16 µm range, for single isolated resonators and large area ensembles, respectively. We show strong tunable absorption resonances (90%) in ensembles of resonators in a significantly broad MIR range. Moreover, by coupling resonators to epsilon-near-zero (ENZ) substrates, we engineer high-Q resonances as high as Q=40. We also show the resonance pinning effect near the substrate ENZ value …

Supplement 1 - A comprehensive theoretical treatment of quasi-static optical parametric amplification in the frequency domain, with an example waveguide design.

W61. 00009: Hidden magnetic memory and spontaneous superconducting vortices in alternating stacking compound 4Hb-TaS 2