Accurate assessment of cell stiffness distribution is essential due to the critical role of cell mechanobiology in regulation of vital cellular processes like proliferation, adhesion, migration, and ...motility. Stiffness provides critical information in understanding onset and progress of various diseases, including metastasis and differentiation of cancer. Atomic force microscopy and optical trapping set the gold standard in stiffness measurements. However, their widespread use has been hampered with long processing times, unreliable contact point determination, physical damage to cells, and unsuitability for multiple cell analysis. Here, we demonstrate a simple, fast, label-free, and high-resolution technique using acoustic stimulation and holographic imaging to reconstruct stiffness maps of single cells. We used this acousto-holographic method to determine stiffness maps of HCT116 and CTC-mimicking HCT116 cells and differentiate between them. Our system would enable widespread use of whole-cell stiffness measurements in clinical and research settings for cancer studies, disease modeling, drug testing, and diagnostics.
Non-Hermitian systems with their spectral degeneracies known as exceptional points (EPs) have been explored for lasing, controlling light transport, and enhancing a sensor’s response. A ring ...resonator can be brought to an EP by controlling the coupling between its frequency degenerate clockwise and counterclockwise traveling modes. This has been typically achieved by introducing two or more nanotips into the resonator’s mode volume. While this method provides a route to study EP physics, the basic understanding of how the nanotips’ shape and size symmetry impact the system’s non-Hermicity is missing, along with additional loss from both in-plane and out-of-plane scattering. The limited resonance stability poses a challenge for leveraging EP effects for switches or modulators, which requires stable cavity resonance and fixed laser-cavity detuning. Here we use lithographically defined asymmetric and symmetric Mie scatterers, which enable subwavelength control of wave transmission and reflections without deflecting to additional radiation channels. We show that those pre-defined Mie scatterers can bring the system to an EP without post tuning, as well as enable chiral light transport within the resonator. Counterintuitively, the Mie scatterer results in enhanced quality factor measured on the transmission port, through coherently suppressing the backscattering from the waveguide surface roughness. The proposed device platform enables pre-defined chiral light propagation and backscattering-free resonances, needed for various applications such as frequency combs, solitons, sensing, and other nonlinear optical processes such as photon blockade, and regenerative oscillators.
Graphical Abstract
We discuss methods of quantum state tomography for solid-state systems with a large nuclear spin I = 3/2 in nanometer-scale semiconductors devices based on a quantum well. Due to quadrupolar ...interactions, the Zeeman levels of these nuclear-spin devices become nonequidistant, forming a controllable four-level quantum system (known as quartit or ququart). The occupation of these levels can be selectively and coherently manipulated by multiphoton transitions using the techniques of nuclear magnetic resonance (NMR) Yusa et al., Nature (London) 434, 1001 (2005) (http://dx.doi.org/10.1038/nature03456). These methods are based on an unconventional approach to NMR, where the longitudinal magnetization M sub(z)is directly measured. This is in contrast to the standard NMR experiments and tomographic methods, where the transverse magnetization M sub(x)yis detected. The robustness against errors in the measured data is analyzed by using the condition number based on the spectral norm. We propose several methods with optimized sets of rotations yielding the highest robustness against errors, as described by the condition number equal to 1, assuming an ideal experimental detection. This robustness is only slightly deteriorated, as given by the condition number equal to 1.05, for a more realistic "noisy" M sub(z)detection based on the standard cyclically ordered phase sequence (CYCLOPS) method.
Engineering light-matter interactions using non-Hermiticity, particularly through spectral degeneracies known as exceptional points (EPs), is an emerging field with potential applications in areas ...such as cavity quantum electrodynamics, spectral filtering, sensing, and thermal imaging. However, tuning and stabilizing a system to a discrete EP in parameter space is a challenging task. Here, we circumvent this challenge by operating a waveguide-coupled resonator on a surface of EPs, known as an exceptional surface (ES). We achieve this by terminating only one end of the waveguide with a tuneable symmetric reflector to induce a nonreciprocal coupling between the frequency-degenerate clockwise and counterclockwise resonator modes. By operating the system at critical coupling on the ES, we demonstrate chiral and degenerate perfect absorption with squared-Lorentzian lineshape. We expect our approach to be useful for studying quantum processes at EPs and to serve as a bridge between non-Hermitian physics and other fields that rely on radiation engineering.
Metal–organic frameworks (MOFs) as methane adsorbents are highly promising materials for applications such as methane‐powered vehicles, flare gas capture, and field natural gas separation. Pre‐ and ...post‐synthetic modification of MOFs have been known to help improve both the overall methane uptake as well as the working capacity. Here, a post‐synthetic modification strategy to non‐covalently modify MOF adsorbents for the enhancement of the natural gas uptake for the MOF material is introduced. In this study, PCN‐250 adsorbents were doped with C10 alkane and C14 fatty acid and their impact on the methane uptake capabilities was investigated. It was found that even trace amounts of heavy hydrocarbons could considerably enhance the raw methane uptake of the MOF while still being regenerable. The doped hydrocarbons are presumably located at the mesoporous defects of PCN‐250, thus optimizing the framework–methane interactions. These findings reveal a general approach that can be used to modify the MOF absorbents, improving their ability to be sustainable and renewable natural gas adsorption platforms.
A non‐covalently modified mesoporous metal–organic framework (MOF) with long‐chain hydrocarbons could significantly increase the already high methane uptake. The long‐chain fatty acid was assumed to be coordinated to the open metal site and located at the mesoporous defects of the MOF. Through optimized partitioning of the mesoporous space of MOF by the doped hydrocarbons, more methane was packed into the pores of the MOF through hydrophobic interactions.
We study mechanical cooling in systems of coupled passive (lossy) and active (with gain) optical resonators. We find that for a driving laser which is red-detuned with respect to the cavity ...frequency, the supermode structure of the system is radically changed, featuring the emergence of genuine high-order exceptional points. This in turn leads to giant enhancement of both the mechanical damping and the spring stiffness, facilitating low-power mechanical cooling in the vicinity of gain-loss balance. This opens up new avenues of steering micromechanical devices with exceptional points beyond the lowest-order two.
We fabricated and theoretically investigated an add-drop filter (ADF) using an on-chip whispering gallery mode (WGM) microtoroid resonator with ultrahigh-quality factor ( Q ) side coupled to two ...taper fibers, forming the bus and drop waveguides. The new device design incorporates silica side walls close to the microresonators which not only enable placing the coupling fibers on the same plane with respect to the microtoroid resonator but also provides mechanical stability, leading to an ADF with high drop efficiency and improved robustness to environmental perturbations. We show that this new device can be thermally tuned to drop desired wavelengths from the bus without significantly affecting the drop efficiency, which is around 57%.
Surgical site infections (SSI) are incomparably troublesome and complicated, and some of them require an open abdomen (OA) procedure. While deciding the timing of abdominal closure, wound area ...calculation method and laboratory parameters can be used to guide the timing of abdominal closure after OA procedures.
The records of the patients who had undergone open abdomen during their treatment course and were followed up with vacuum-assisted closure (VAC) technique between December 2015 and December 2019 were retrospectively analyzed. The laboratory results before the first VAC application and the results after the VAC change were compared to determine a predictive parameter. The ImageJ program was used in five patients to compare the size of the wounds at the time of the decision to close them and before the first VAC application.
102 patients were analyzed. The ratio of the last wound area to the wound area at the time of the first VAC application in five patients was 0.30, 0.41, 0.34, 0.27, 0.46 (mean: 0.36, standard deviation: 0.078) which were measured and calculated by ImageJ software.
We think that the concept of wound reduction ratio, which was calculated by a computer program, can be used as a concrete equivalent of the wound closure eligibility criteria decided by clinical experience.
Amidst the evident challenges posed by brain tumors and the evident limitations of conventional treatment methodologies like surgery, radiotherapy, and chemotherapy, our primary objective was to ...probe the therapeutic potential of high-intensity therapeutic ultrasound (HITU). The aim was to introduce a safer, cost-effective, and efficient alternative to existing treatments, especially beneficial for inaccessible brain tumor sites and resource-constrained medical facilities.
Leveraging post-1990s MR technology advancements, we employed the non-invasive HITU technique, akin to high-intensity focused ultrasound. This method directs acoustic energy to tissues, primarily inducing coagulation necrosis by absorbing energy and elevating tissue temperatures. Glial tumor cells were subjected to HITU to assess its effects.
Upon applying HITU to glial tumor cells, significant alterations in cellular structural integrity were evident. The main action of HITU was the absorption of acoustic energy, leading to a notable temperature rise and coagulation necrosis. Flow cytometry indicated significant cellular changes post-HITU. ANOVA and t-test analyses showed a significant relationship between HITU application and time (p<0.05). The Shapiro-Wilk test revealed non-normal data distribution (p<0.05), leading to the use of nonparametric methods. The t-test results after HITU displayed significant differences (p<0.05) in cell counts and fluorescence intensity between control and treated groups. This result was consistent across multiple tests, indicating the reliability of the method in causing cellular damage to the tumor cells.
Our laboratory analyses offer compelling evidence that HITU is not merely feasible but is also a promising non-invasive approach in the treatment paradigm of brain tumors. Standing distinctively apart from radiotherapy, HITU averts early, or late complications commonly associated with the former. While the path ahead mandates comprehensive research to ascertain its clinical utility, preliminary indications firmly posit HITU as a groundbreaking prospect in the management of brain tumors.
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