Three-dimensional rainbow refractometry.

We propose a new, to the best of our knowledge, rainbow technique called three-dimensional rainbow refractometry (TDRR), with a cylindrical lens in the signal collecting system. With a TDRR model based on the ray transfer matrix developed, it is proved that the tilt angle of the rainbow signal is related to the axial position of the droplet, which helps to obtain the 3D position. By converting rainbow scattering angle calibration into the system parameter calibration, a new rainbow data processing program is written in combination with the model to obtain the refractive index and the particle size. With TDRR, we measured a monodisperse droplet stream of deionized water at room temperature for experimental validation and obtained the refractive index with an absolute error of less than 0.0015, the droplet size with an error within ±5%, and the axial position with an error within ±3%, which demonstrated a high accuracy of TDRR.

Spectroscopic Techniques and Hydrogen-Sensitive Compounds: A New Horizon in Hydrogen Detection.

Detecting hydrogen leaks remains a pivotal challenge demanding robust solutions. Among diverse detection techniques, the fiber-optic method distinguishes itself through unique benefits, such as its distributed measurement properties. The adoption of hydrogen-sensitive materials coated on fibers has gained significant traction in research circles, credited to its operational simplicity and exceptional adaptability across varied conditions. This manuscript offers an exhaustive investigation into hydrogen-sensitive materials and their incorporation into fiber-optic hydrogen sensors. The research profoundly analyzes the sensor architectures, performance indicators, and the spectrum of sensing materials. A detailed understanding of these sensors' potentials and constraints emerges through rigorous examination, juxtaposition, and holistic discourse. Furthermore, this analysis judiciously assesses the inherent challenges tied to these systems, simultaneously highlighting potential pathways for future innovation. By spotlighting the hurdles and opportunities, this paper furnishes a view on hydrogen sensing technology, particularly related to optical fiber-based applications.

Integrated Flexible Microscale Mechanical Sensors Based on Cascaded Free Spectral Range-Free Cavities.

Photonic mechanical sensors offer several advantages over their electronic counterparts, including immunity to electromagnetic interference, increased sensitivity, and measurement accuracy. Exploring flexible mechanical sensors on deformable substrates provides new opportunities for strain-optical coupling operations. Nevertheless, existing flexible photonics strategies often require cumbersome signal collection and analysis with bulky setups, limiting their portability and affordability. To address these challenges, we propose a waveguide-integrated flexible mechanical sensor based on cascaded photonic crystal microcavities with inherent deformation and biaxial tensile state analysis. Leveraging the advanced multiplexing capability of the sensor, for the first time, we successfully demonstrate 2D shape reconstruction and quasi-distributed strain sensing with 110 µm spatial resolution. Our microscale mechanical sensor also exhibits exceptional sensitivity with a detected force level as low as 13.6 µN in real-time measurements. This sensing platform has potential applications in various fields, including biomedical sensing, surgical catheters, aircraft and spacecraft engineering, and robotic photonic skin development.

Endovascular Treatment Versus Best Medical Management in Acute Basilar Artery Occlusion Strokes: Results From the ATTENTION Multicenter Registry.

BACKGROUND: The authors compare the effectiveness and safety of endovascular treatment (EVT) versus best medical management (BMM) in strokes attributable to acute basilar artery occlusion (BAO). METHODS: The present analysis was based on the ongoing, prospective, multicenter ATTENTION (Endovascular Treatment for Acute Basilar Artery Occlusion) trial registry in China. Our analytic sample comprised 2134 patients recruited at 48 sites between 2017 and 2021 and included 462 patients who received BMM and 1672 patients who received EVT. We performed an inversed probability of treatment weighting analysis. Qualifying patients had to present within 24 hours of estimated BAO. The primary clinical outcome was favorable functional outcome (modified Rankin Scale score, 0-3) at 90 days. We also performed a sensitivity analysis with the propensity score matching-based and the instrumental variable-based analysis. RESULTS: In our primary analysis using the inversed probability of treatment weighting-based analysis, there was a significantly higher rate of favorable outcome at 90 days among EVT patients compared with BMM-treated patients (adjusted relative risk, 1.42 [95% CI, 1.19-1.65]; absolute risk difference, 11.8% [95% CI, 6.9-16.7]). The mortality was significantly lower (adjusted relative risk, 0.78 [95% CI, 0.69-0.88]; absolute risk difference, -10.3% [95% CI, -15.8 to -4.9]) in patients undergoing EVT. Results were generally consistent across the secondary end points. Similar associations were seen in the propensity score matching-based and instrumental variable-based analysis. CONCLUSIONS: In this real-world study, EVT was associated with significantly better functional outcomes and survival at 90 days. Well-designed randomized studies comparing EVT with BMM in the acute BAO are needed. REGISTRATION: URL: www.chictr.org.cn; Unique identifier: ChiCTR2000041117.

Mitochondrial-Targeting Near-Infrared Fluorescent Probe for Visualizing Viscosity in Drug-Induced Cells and a Fatty Liver Mouse Model.

Mitochondria, as "cell energy stations", are involved in the regulation of various cell functions. Recent investigations revealed that mitochondrial dysfunction that can cause an intracellular viscosity mutation, a process that is associated with an increasing number of diseases that are not curable or manageable. However, conventional viscometers cannot be used to monitor the viscosity changes in living cells and in vivo. In order to cater to the complex biological environment, we present a chemical toolbox, MI-BP-CC, that employs N,N-diethyl and double bonds as sensitive sites for viscosity based on the TICT mechanism (twisted intramolecular charge transfer) to monitor the viscosity of living cells and fatter liver mice. MI-BP-CC features good mitochondrial targeting and a near-infrared emission. Surprisingly, in the presence of viscosity, the MI-BP-CC probe exhibited an ultrasensitive model for viscosity detection showing a red fluorescence signal from a silent "off" state to "on". More importantly, utilizing the satisfactory detection performance of MI-BP-CC, we have successfully visualized increased viscosity under the pathological models of Parkinson's (PD) and fatty liver mice. We anticipate that these findings will provide a convenient and efficient tool to understand physiological functions of viscosity in more biosystems.

Accurate droplet depth displacement measurement with time-resolved astigmatic interferometric particle imaging.

The astigmatic interferometric particle imaging (AIPI) model reveals that the fringe orientation shifts with droplet depth displacement, and their relationships are quantitatively formulated. The depth displacement is directly evaluated from the relative angular shift of the fringes with angular cross power spectral density, and this algorithm isolates the uncertainty of droplet depth position from depth displacement. Proof-of-concept experiments on micrometer-sized transparent droplets with a 5 kHz AIPI system demonstrates that droplet three-dimensional (3D) trajectories are accurately obtained with the accuracy of depth displacement up to tens of micrometers, improving an order of magnitude from hundreds of microns in a traditional Lagrangian framework by comparing droplet depth positions.

Synthetic aperture rainbow refractometry.

This work proposed a synthetic aperture rainbow refractometry (SARR) by synthesizing rainbow signals of the same droplet with dual-wavelength laser beams, in order to increase the aperture of rainbow refractometry. In this way, the SARR can apply to long distance and small droplets measurement. An achromatic imaging system, which simultaneously records while separating the two rainbow signals in two channels of a color image, is elaborately designed. A data processing algorithm is developed to retrieve the optimal droplet refractive index and size. Numerical simulations of different droplet sizes from 10 µm to 200 µm certify the viability of the SARR. Proof-of-concept experiments of micron-sized ethanol droplets are performed with 1650 mm measurement distance. Results show that the SARR can accurately measure droplet refractive index and size with uncertainties of 2.3 × 10-4 and 2µm, respectively. The feasibility and accuracy of the proposed SARR are successfully demonstrated, paving the way for rainbow refractometry applied to large-scale industrial applications.

Chemical degrader enhances the treatment of androgen receptor-positive triple-negative breast cancer.

Androgen receptor (AR) is a promising therapeutic target for AR-positive triple-negative breast cancer (TNBC). However, clinical trials of AR inhibitors only reveal modest therapeutic efficacy for AR-positive TNBC, and drug resistance is also inevitable. To address these challenges, we herein report the use of an AR-targeting proteolysis targeting chimera (AR-PROTAC) to treat AR-positive TNBC. We demonstrated that AR-PROTAC potently degraded AR protein via the ubiquitin-proteasome pathway in AR-positive TNBC BT549 cells, with a half degradation concentration of ∼46.9 nM. By evaluating the therapeutic efficacies in vitro and in vivo, we validated that AR-PROTAC was superior to enzalutamide, an AR inhibitor. Specifically, AR-PROTAC at 100 nM reduced BT549 cell viability by up to ∼80%, and AR-PRTOAC at 10 mg/kg suppressed tumor growth by ∼60% when administrated intratumorally in subcutaneous BT549 tumor mice model. Overall, these results demonstrate for the first time that PROTAC holds promise to enhance the treatment of AR-positive TNBC.

Surface temperature measurement of cooling and heating droplets by rainbow refractometry.

Rainbow refractometry was used to measure the temperature and size of transparent spherical particles. In practice, however, there are limitations to the application of heating and cooling droplets, as the temperature measured is neither the average nor the surface or core temperature of the droplet. Reported here is an exploitation of this technique for droplet surface temperature determination. Droplet surface tension was measured by detecting the evolution of interference fringes of oscillating droplets. The dependence of surface tension on temperature facilitated the study of surface temperature of an evaporating droplet with time. Moving ethanol, n-heptane, and n-decane droplets were investigated under heating and cooling conditions. The capabilities and limitations of rainbow refractometry were verified by comparing the droplet temperature values measured directly by rainbow refractometry with the surface temperature.

Astigmatic dual-beam interferometric particle imaging for metal droplet 3D position and size measurement.

We propose astigmatic dual-beam interferometric particle imaging (ADIPI) to simultaneously measure the three-dimensional (3D) position and size of spherical metal droplets. A theoretical model reveals that the orientation and spacing of the ADIPI fringes generated from the two reflections propagating through an astigmatic imaging system relate to the depth position and size, respectively. Proof-of-concept experiments on micron-sized gallium droplets are performed, and the tilted fringes in elliptical patterns are observed in the ADIPI interferogram, confirming theoretical predictions. Droplet 3D position and size are determined with ADIPI, and the relative discrepancies are within 5% and 2% compared to those with a dual-view digital inline holography system, demonstrating the feasibility and high accuracy of ADIPI.

Planar rainbow refractometry.

Rainbow refractometry has been used in the past to measure size and refractive index of spherical particles, typically droplets in a spray. In the present study, conventional optical configurations for point measurements or line measurements have been extended to allow also the particle position in a plane to be determined, and hence, the designation planar rainbow refractometry. However, this extension introduces challenges in accurately calibrating the 2D scattering angles with the image coordinates. This challenge has been met using a novel calibration method, employing a monodispersed droplet stream traversed through the measurement plane. Experiments confirm achievable horizontal and vertical position accuracies of 0.42 mm and 0.36 mm, respectively, and a refractive index uncertainty of 2×10-4.

Measurement of airblast atomization of low temperature kerosene with 25 kHz digital holography.

Atomization of low temperature fuel is of great importance in a jet engine combustor, and its visualization and diagnostics are challenging, especially in the presence of shreds and ligaments. A 25 kHz picosecond pulsed digital inline holography system is applied to measure the spray produced by an airblast atomizer with low temperature kerosene. The breakup process of shreds and ligaments of -37∘C kerosene are visualized and analyzed, revealing the transition of liquid jet disintegrating into droplets under the atomizing air film. Three-dimensional positions and size distributions of droplets in spray are acquired. It is found that a decrease in the kerosene temperature increases shreds and ligaments in the spray, which eventually leads to reduction of droplet density and increase of droplet size, while increasing the air pressure can compensate the degradation. This work also demonstrates that high speed holographic imaging is a powerful tool in spray diagnostics and liquid breakup visualization.

Surface tension and viscosity measurement of oscillating droplet using rainbow refractometry.

We extend rainbow refractometry to quantify the oscillations of a droplet in its fundamental mode. The oscillation parameters (frequency and amplitude damping), extracted using the time-resolved rainbow angular shift, are utilized to measure surface tension and viscosity of the liquid. Proof-of-concept experiments on an oscillating droplet stream produced by a monodisperse droplet generator are conducted. Results show that the relative measurement errors of surface tension and viscosity are 1.5% and 8.4% for water and 5.3% and 2.5% for ethanol. This approach provides an alternative mean for characterizing liquid surface properties, e.g., dynamic surface tension and viscosity, especially for liquids with a low Ohnesorge number.

Phase critical angle scattering for measurement of transient nanoscale growth rate of a micron-sized bubble.

We developed phase critical angle scattering (PCAS) to simultaneously measure the spherical and transparent bubble size at the micron scale and transient bubble growth at the nanoscale. The theoretical derivation of PCAS reveals that the phase of the fine structure of critical angle scattering caused by reflection and first-order refraction is highly sensitive to and linearly shifts with bubble diameter growth. Experiments on a single growing bubble are implemented with a Fourier imaging system. The results show that the PCAS technique can measure the tiny bubble growth down to tens of nanometers, providing a promising tool for accurate characterization of bubble dynamics.

Accurate detection of small particles in digital holography using fully convolutional networks.

Particle detection is a key procedure in particle field characterization with digital holography. Due to various background noises, spurious small particles might be generated and real small particles might be lost during particle detection. Therefore, accurate small particle detection remains a challenge in the research of energy and combustion. A deep learning method based on modified fully convolutional networks is proposed to detect small opaque particles (e.g., coal particles) on extended focus images. The model is tested by several experiments and proved to have good small particle detection accuracy.

Chelerythrine Inhibits Human Hepatocellular Carcinoma Metastasis in Vitro.

Chelerythrine (CHE) is a type of benzophenanthridine alkaloid found in many herbs and is also the main alkaloid constituent of Toddalia asiatica (L.) LAM. It has been proven to have various activities including antitumor, antifungal, anti-inflammatory and anti-parasitic effects. We have previously demonstrated that CHE can inhibit proliferation and promote apoptosis in human hepatocellular carcinoma (HCC) cells. However, the effect of CHE on the metastasis of HCC and its related molecular mechanisms have yet to be validated. In this study, we investigated the effects of CHE on the migration and invasion of the HCC cell line Hep3B. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wounding healing, transwell migration and invasion assays and cytoskeleton staining demonstrated that CHE could inhibit the migration and invasion of Hep3B cells in a dose-dependent manner with change of cell structure. RNA interference studies made a knockdown of matrix metalloproteinase (MMP)-2/9 respectively in Hep3B cells. And the results of wounding healing and transwell invasion assay with the treatment of small interfering RNA (siRNA) investigated that MMP-2/9 are positively associated with Hep3B cell metastasis. The results of enzyme-linked immunosorbent assay (ELISA), Western blotting and quantitative RT-PCR showed that CHE suppressed the expression of MMP-2/9 at both mRNA and protein levels. CHE also exhibited an inhibitory effect on the phosphorylation of Focal adhesion kinase (FAK), phosphatidylinositol 3-kinase (PI3K), Akt, mammalian target of rapamycin (mTOR), c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinases (ERK) and p38. In summary, on Hep3B cells, CHE could change the cell cytoskeletal structures through reducing the expression of p-FAK and inhibit the metastasis of Hep3B cells by downregulating the expression of MMP-2/9 mainly through PI3K/Akt/mTOR signaling pathway.

Three-dimensional characterization of debris clouds under hypervelocity impact with pulsed digital inline holography.

The increasing space debris poses a great threat to in-orbit spacecraft and satellites, because its hypervelocity impact can bring about fatal mechanical and electrical damage to them. This work applies pulsed digital inline holography (DIH) to measure three-dimensional (3D) positions and shapes of the debris clouds generated by the hypervelocity impact in the Whipple shield. Detailed operation procedures of synchronizing the pulse DIH system with the impact event and removing the strong plasma radiation are presented, ensuring the successful capture of the transient state of ultrafast ejecta. Experiments on a 2.25 mm aluminum sphere impacting a 0.5 mm thickness aluminum target plate with a velocity of 3.6 km/s are carried out at the Hypervelocity Impact Research Center of the China Aerodynamics Research and Development Center, and results show that the holographic fringes are clearly recorded and the debris fragments are reconstructed and located accurately, agreeing well with the results measured by laser shadowgraph. This work demonstrates the powerful capability and great potential of DIH in the diagnostics of hypervelocity impact.

Phase rainbow refractometry for accurate droplet variation characterization.

We developed a one-dimensional phase rainbow refractometer for the accurate trans-dimensional measurements of droplet size on the micrometer scale as well as the tiny droplet diameter variations at the nanoscale. The dependence of the phase shift of the rainbow ripple structures on the droplet variations is revealed. The phase-shifting rainbow image is recorded by a telecentric one-dimensional rainbow imaging system. Experiments on the evaporating monodispersed droplet stream show that the phase rainbow refractometer can measure the tiny droplet diameter changes down to tens of nanometers. This one-dimensional phase rainbow refractometer is capable of measuring the droplet refractive index and diameter, as well as variations.

Characterizations of transparent particle holography in near-field using Debye series.

The effects of the individual scattering process on the formations of both the particle hologram and its corresponding reconstructed three-dimensional particle image are investigated using the Debye series. A particle hologram model using the Debye series decomposes the object wave into different scattering modes and thus permits evaluating the effects of the individual scattering process [diffraction, reflection, transmission, refractions with (p-1) internal reflections] on the particle holography quantitatively. In the Gabor inline holography of a transparent droplet, the transmission light causes small discrepancies between the hologram fringes of an opaque particle (diffraction) and a transparent particle near the zero point of the Bessel-like modulation function, eventually giving rise to the glory spot in the center of the reconstructed dark particle image. For off-axis holography, this paper reveals the effects of reflection, particularly total reflection by bubbles, transmission, and refractions with (p-1) internal reflections of the scattered light on the formation and the reconstructed glory spot images of typical forward and backward off-axis holography.

One-dimensional rainbow technique using Fourier domain filtering.

Rainbow refractometry can measure the refractive index and the size of a droplet simultaneously. The refractive index measurement is extracted from the absolute rainbow scattering angle. Accordingly, the angular calibration is vital for accurate measurements. A new optical design of the one-dimensional rainbow technique is proposed by using a one-dimensional spatial filter in the Fourier domain. The relationship between the scattering angle and the CCD pixel of a recorded rainbow image can be accurately determined by a simple calibration. Moreover, only the light perpendicularly incident on the lens in the angle (φ) direction is selected, which exactly matches the classical inversion algorithm used in rainbow refractometry. Both standard and global one-dimensional rainbow techniques are implemented with the proposed optical design, and are successfully applied to measure the refractive index and the size of a line of n-heptane droplets.