BINA

Using hyperspectral measurements, J‐aggregate nanorods of porphyrin molecules embedded in plasmonic Au nanoparticles arrays are studied. Measurements of J‐aggregate nanorods that cross onto a plasmonic array exhibit a shift in their absorption peak, and display weak coupling properties only for the embedded part. Furthermore, a significant thickness‐dependent redshift in the plasmonic resonance for the J‐aggregate clusters is observed. Such redshift is also dependent on the ratio of J‐aggregate in the plasmonic dipole interaction area, reaching values of up to 120 meV for ≈40% coverage. In addition, for large clusters of J‐aggregates, the plasmonic spectrum shows coupling behavior between the systems indicated by a small Rabi splitting. The findings are validated by a quasi‐static model based on the change of the dielectric environment around the embedded nanoparticles. Using the model, the …

Plasmonic nano-objects have shown great potential in enhancing applications like biological/chemical sensing, light harvesting and energy transfer, and optical/quantum computing. Therefore, an extensive effort has been vested in optimizing plasmonic systems and exploiting their field enhancement properties. Super-resolution imaging with quantum dots (QDs) is a promising method to probe plasmonic near-fields but is hindered by the distortion of the QD radiation pattern. Here, we investigate the interaction between QDs and “L-shaped” gold nanoantennas and demonstrate both theoretically and experimentally that this strong interaction can induce polarization-dependent modifications to the apparent QD emission intensity, polarization, and localization. Based on FDTD simulations and polarization-modulated single-molecule microscopy, we show that the displacement of the emitter’s localization is due to the …

Anderson localization predicts that transport in one-dimensional uncorrelated disordered systems comes to a complete halt, experiencing no transport whatsoever. However, in reality, a disordered physical system is always correlated because it must have a finite spectrum. Common wisdom in the field states that localization is dominant only for wave packets whose spectral extent resides within the region of the wave number span of the disorder. Here, we show experimentally that Anderson localization can occur and even be dominant for wave packets residing entirely outside the spectral extent of the disorder. We study the evolution of wave packets in synthetic photonic lattices containing bandwidth-limited (correlated) disorder and observe strong localization for wave packets centered at twice the mean wave number of the disorder spectral extent and at low wave numbers, both far beyond the spectrum of the …

We shows, how real time spatial shaping of pump profile imposed on a strongly scattering gain medium can be used to achieve single mode lasing at pre-selected target wavelength. Simultaneously, near field imaging of the sample surface from the top allow us to record field distribution of the localized modes. We show that slope efficiency of Ander-son localized lasing mode enhanced by one order magnitude under selective pumping.

We investigate a tight-binding quantum walk on a graph. Repeated stroboscopic measurements of the position of the particle yield a measured “trajectory,” and a combination of classical and quantum mechanical properties for the walk are observed. We explore the effects of the measurements on the spreading of the packet on a one-dimensional line, showing that except for the Zeno limit, the system converges to Gaussian statistics similarly to a classical random walk. A large deviation analysis and an Edgeworth expansion yield quantum corrections to this normal behavior. We then explore the first passage time to a target state using a generating function method, yielding properties like the quantization of the mean first return time. In particular, we study the effects of certain sampling rates that cause remarkable changes in the behavior in the system, such as divergence of the mean detection time in finite systems …

Coral reefs are in global decline due to climate change and anthropogenic influences (Hughes et al., Conservation Biology, 27: 261–269, 2013). Near coastal cities or other densely populated areas, coral reefs face a range of additional challenges. While considerable progress has been made in understanding coral responses to acute individual stressors (Dominoni et al., Nature Ecology & Evolution, 4: 502–511, 2020), the impacts of chronic exposure to varying combinations of sensory pollutants are largely unknown. To investigate the impacts of urban proximity on corals, we conducted a year‐long in‐natura study—incorporating sampling at diel, monthly, and seasonal time points—in which we compared corals from an urban area to corals from a proximal non‐urban area. Here we reveal that despite appearing relatively healthy, natural biorhythms and environmental sensory systems were extensively disturbed …

In the vicinity of a narrow Feshbach resonance Efimov features are expected to be characterized by the resonance's properties rather than the van der Waals length of the interatomic potential. Although this theoretical prediction is well established by now, it still lacks experimental confirmation. Here, we apply our recently developed three-channel model [Y. Yudkin and L. Khaykovich, Efimov scenario for overlapping narrow Feshbach resonances, Phys. Rev. A 103, 063303 (2021)] to the experimental result obtained in a mass-imbalanced Li 6− Cs 133 mixture in the vicinity of the narrowest resonance explored to date [J. Johansen, BJ DeSalvo, K. Patel, and C. Chin, Testing universality of Efimov physics across broad and narrow Feshbach resonances, Nat. Phys. 13, 731 (2017)]. Our analysis suggests that the observed position of the Efimov resonance is dictated mainly by the resonance physics while the influence of …

Tailoring the precise construction of non‐precious metals and carbon‐based heterogeneous catalysts for electrochemical oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) is crucial for energy conversion applications. Herein, this work reports the composite of Ni doped Fe2O3 (Ni−Fe2O3) with mildly oxidized multi‐walled CNT (O−CNT) as an outstanding Mott‐Schottky catalyst for OER and MOR. O−CNT acts as a co‐catalyst which effectively regulates the charge transfer in Ni−Fe2O3 and thus enhances the electrocatalytic performance. Ni−Fe2O3/O−CNT exhibits a low onset potential of 260 mV and overpotential 310 mV @ 10 mA cm−2 for oxygen evolution. Being a Mott‐Schottky catalyst, it achieves the higher flat band potential of −1.15 V with the carrier density of 0.173×1024 cm−3. Further, in presence of 1 M CH3OH, it delivers the MOR current density of 10 mA cm−2 at 1.46 V …

Near-infrared (NIR) fluorescence lifetime imaging (FLI) provides a unique contrast mechanism to monitor biological parameters and molecular events in vivo. Single-photon avalanche diode (SPAD) cameras have been recently demonstrated in FLI microscopy (FLIM) applications, but their suitability for in vivo macroscopic FLI (MFLI) in deep tissues remains to be demonstrated. Herein, we report in vivo NIR MFLI measurement with SwissSPAD2, a large time-gated SPAD camera. We first benchmark its performance in well-controlled in vitro experiments, ranging from monitoring environmental effects on fluorescence lifetime, to quantifying Förster resonant energy transfer (FRET) between dyes. Next, we use it for in vivo studies of target-drug engagement in live and intact tumor xenografts using FRET. Information obtained with SwissSPAD2 was successfully compared to that obtained with a gated intensified charge-coupled device (ICCD) camera, using two different approaches. Our results demonstrate that SPAD cameras offer a powerful technology for in vivo preclinical applications in the NIR window.

Epithelial–mesenchymal Transition (EMT) is a multi-step process that involves cytoskeletal rearrangement. Here, developing and using an image quantification tool, Statistical Parametrization of Cell Cytoskeleton (SPOCC), we have identified an intermediate EMT state with a specific cytoskeletal signature. We have been able to partition EMT into two steps: (1) initial formation of transverse arcs and dorsal stress fibers and (2) their subsequent conversion to ventral stress fibers with a concurrent alignment of fibers. Using the Orientational Order Parameter (OOP) as a figure of merit, we have been able to track EMT progression in live cells as well as characterize and quantify their cytoskeletal response to drugs. SPOCC has improved throughput and is non-destructive, making it a viable candidate for studying a broad range of biological processes. Further, owing to the increased stiffness (and by inference invasiveness …

Metalloregulators bind and respond to metal ions by regulating the transcription of metal homeostasis genes. Copper efflux regulator (CueR) is a copper‐responsive metalloregulator that is found in numerous Gram‐negative bacteria. Upon Cu(I) coordination, CueR initiates transcription by bending the bound DNA promoter regions facilitating interaction with RNA polymerase. The structure of Escherichia coli CueR in presence of DNA and metal ion has been reported using X‐ray crystallography and cryo‐EM, providing information about the mechanism of action. However, the specific role of copper in controlling this transcription mechanism remains elusive. Herein, we use room temperature electron paramagnetic resonance (EPR) experiments to follow allosterically driven dynamical changes in E. coli CueR induced by Cu(I) binding. We suggest that more than one Cu(I) ion binds per CueR monomer, leading to …

Nitrogen-vacancy (NV) center in diamond is a promising quantum sensor with remarkably versatile sensing capabilities. While scanning NV magnetometry is well-established, NV electrometry has been so far limited to bulk diamonds. Here we demonstrate imaging external alternating (AC) and direct (DC) electric fields with a single NV at the apex of a diamond scanning tip under ambient conditions. A strong electric field screening effect is observed at low frequencies due to charge noise on the surface. We quantitatively measure its frequency dependence, and overcome this screening by mechanically oscillating the tip for imaging DC fields. Our scanning NV electrometry achieved an AC E-field sensitivity of 26 mV um^(-1) Hz^(-1/2), a DC E-field gradient sensitivity of 2 V um^(-2) Hz^(-1/2), and sub-100 nm resolution limited by the NV-sample distance. Our work represents an important step toward building a scanning-probe-based multimodal quantum sensing platform.

The TP53 gene is mutated in approximately 60% of all colorectal cancer (CRC) cases. Over 20% of all TP53-mutated CRC tumors carry missense mutations at position R175 or R273. Here we report that CRC tumors harboring R273 mutations are more prone to progress to metastatic disease, with decreased survival, than those with R175 mutations. We identify a distinct transcriptional signature orchestrated by p53R273H, implicating activation of oncogenic signaling pathways and predicting worse outcome. These features are shared also with the hotspot mutants p53R248Q and p53R248W. p53R273H selectively promotes rapid CRC cell spreading, migration, invasion and metastasis. The transcriptional output of p53R273H is associated with preferential binding to regulatory elements of R273 signature genes. Thus, different TP53 missense mutations contribute differently to cancer progression. Elucidation of the …

“However, this technique suffers from the fact that it requires a lot of image processing tools, and post processing”“Another interesting approach is to exploit the memory effect of speckles. Memory effect states that there exists a correlation between a speckle pattern even when the laser illumination is tilted within a given angular range. Freund12, 13 used the scattering media as a lens based on speckle intensity correlation. This idea was extended by Bertolotti et al. 14 to image a fluorescent object behind the media.” now reads:“Another interesting approach is to exploit the memory effect of speckles. Memory effect states that there exists a correlation between a speckle pattern even when the laser illumination is tilted within a given angular range. Freund12–14 used the scattering media as a lens based on speckle intensity correlation. This idea was extended by Bertolotti et al. 13 to image a fluorescent object behind …

Utilizing a combination of hyperspectral measurements and sorting K-means algorithms, we study coupled J-aggregate–plasmonic nanostructures system. The effect of proximity and cover ratio of the J-aggregates on the plasmonic resonance is shown and modeled.

Tailoring the precise construction of non‐precious metals and carbon‐based heterogeneous catalysts for electrochemical oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) is crucial for energy conversion applications. Herein, this work reports the composite of Ni doped Fe2O3 (Ni−Fe2O3) with mildly oxidized multi‐walled CNT (O−CNT) as an outstanding Mott‐Schottky catalyst for OER and MOR. O−CNT acts as a co‐catalyst which effectively regulates the charge transfer in Ni−Fe2O3 and thus enhances the electrocatalytic performance. Ni−Fe2O3/O−CNT exhibits a low onset potential of 260 mV and overpotential 310 mV @ 10 mA cm−2 for oxygen evolution. Being a Mott‐Schottky catalyst, it achieves the higher flat band potential of −1.15 V with the carrier density of 0.173×1024 cm−3. Further, in presence of 1 M CH3OH, it delivers the MOR current density of 10 mA cm−2 at 1.46 V …

Diabetic foot is a well-known problem among patients suffering from peripheral arterial diseases (PAD). This article presents an optical sensor for contactless measurement of the anatomical site based on laser speckle techniques. The sensor illuminates the inspected tissue and analyzes the captured back-reflected light from the time-changing speckle patterns. An occlusion test was implemented to provide a statistical parameter to differentiate between a low perfused and a healthy foot. A clinical study of 15 subjects was conducted. The video was analyzed by two methods: dynamic laser speckle (DLS) and laser speckle contrast analysis (LASCA). Data analysis included several classification models, where the KNN model exhibited maximum performance. These findings suggest that a simple and inexpensive system for PAD monitoring can be designed for home use and/or in community clinics.

The wavefront is scrambled when coherent light propagates through a random scattering medium and which makes direct use of the conventional optical methods ineffective. In this paper, we propose and demonstrate a structured light illumination for imaging through an opaque scattering layer. Proposed technique is reference free and capable to recover the complex field from intensities of the speckle patterns. This is realized by making use of the phase-shifting in the structured light illumination and applying spatial averaging of the speckle pattern in the intensity correlation measurement. An experimental design is presented and simulated results based on the experimental design are shown to demonstrate imaging of different complex-valued objects through scattering layer.