Repairing distorted hologram data for sound field reconstruction.

This paper proposes a distorted hologram data repair approach for sound field reconstruction. In this approach, an equivalent source model is established by placing a set of equivalent sources near the hologram surface to represent the measured hologram pressures. Each hologram pressure is simultaneously assigned an indicator to describe whether its measurement is corrupted by errors or not. This model is then formulated within a modal framework by utilizing the modes generated through the singular value decomposition of the transfer matrix between the hologram and nearby equivalent source surfaces. Subsequently, the indicators and modal coefficients are assigned the 0-1 and Gaussian prior distributions, respectively, and their posterior distributions are derived using the Bayesian method. The means of the posterior distributions are calculated to discriminate corrupted measurements and repair distorted hologram pressures. Repaired hologram pressures are finally utilized for reconstructions using the equivalent source method. Results from both numerical simulations conducted under various parameter settings and two experiments demonstrate the effectiveness of the proposed approach in automatically discriminating all the corrupted measurements and accurately repairing the distorted hologram pressures. Furthermore, the accuracy of the reconstructions using the repaired hologram pressures is comparable to that achieved with the correctly measured pressures.

Real-time nearfield acoustic holography using particle velocity.

In this paper, a series of impulse response functions between acoustic quantities on the source plane and particle velocity on the hologram plane are derived. In virtue of these functions, real-time nearfield acoustic holography (RT-NAH) is extended from pressure-based to particle velocity. Pressure, normal velocity, acceleration, and displacement radiated from planar sources can be reconstructed by measuring time-dependent particle velocity signals on the hologram plane. A simulation of an excited aluminum plate is performed to evaluate the difference in accuracy between RT-NAHs based on pressure and based on particle velocity. This study also examines the impact of impulse response functions on the reconstruction results, allowing for detailed analysis of the reconstruction accuracy based on these functions. The simulation results demonstrate that using RT-NAH based on particle velocity obtains significantly higher-accuracy reconstruction results when reconstructing normal velocity and displacement and slightly more accurate reconstructed pressure and normal acceleration.

The causal effects of age at menarche, age at first live birth, and estradiol levels on systemic lupus erythematosus: A two-sample Mendelian randomization analysis.

OBJECTIVES: To determine whether age at menarche (AAM), age at first live birth (AFB), and estradiol levels are causally correlated with the development of systemic lupus erythematosus (SLE). METHODS: A two-sample Mendelian randomization (MR) analysis was performed after data was collected from a dataset of genome-wide association studies (GWASs) related to SLE (as outcome), and from open access databases to find statistics related to AAM, AFB, and estradiol levels (as exposure). RESULT: In our study, a negative causal correlation between AAM and SLE was confirmed by MR analysis (MR egger: beta = 0.116, SE = 0.948, p = 0.909; weighted median: beta = -0.416, SE = 0.192, p = 0.030; and IVW: beta = -0.395, SE = 0.165, p = 0.016). However, there were no genetic causal effects of AFB and the estradiol levels on SLE, based on the results of MR analysis as follows: AFB (MR egger: beta = - 2.815, SE = 1.469, p = 0.065; Weighted median: beta = 0.334, SE = 0.378, p = 0.377; and IVW: beta = 0.188, SE = 0.282, p = 0.505) and the estradiol levels (MR egger: beta = 0.139, SE = 0.294, p = 0.651; weighted median: beta = 0.063, SE = 0.108, p = 0.559; IVW: beta = 0.126, SE = 0.097, p = 0.192). CONCLUSIONS: Our findings revealed that AAM may be associated with increased risk of the development of SLE, while there were no such causal effects from AFB and estradiol levels.

A near-infrared fluorescent probe for in situ imaging of SO2 flux in drug-induced liver injury.

Sulfur dioxide (SO2) has been widely applied as an important additive in various foods and drugs due to its antioxidant, antiseptic and bleaching properties. SO2 in living organisms plays a key biological role as an antioxidant in a variety of life activities. However, abnormal levels of SO2 in both food and living organisms could cause harm and even serious illness, such as diseases related to the respiratory and cardiovascular systems and cancers. Therefore, it is of great practical significance to accurately determine the level of SO2 in food and organisms. In this work, we synthesized a novel near-infrared ratiometric fluorescent probe (NTO) using xanthene and benzopyran as the matrix for the detection of SO2. NTO demonstrates a rapid response (within 8 s), high selectivity, excellent sensitivity (LOD = 3.64 µM) and a long emission wavelength (800 nm), which could be applied to SO2 monitoring in a complex environment. NTO showed a high recovery (90%-110%) of SO2 in food samples such as beer and rock sugar. The results of HeLa cell experiments indicate that NTO has excellent fluorescence labeling ability for SO2 in endoexogenous-sulfide metabolism. In addition, we applied it to mice with acetaminophen (APAP)-induced acute liver injury and observed changes in SO2 during liver injury. Based on these results, we believe that this will provide a convenient visual tool for the detection of the SO2 content in food safety and biomedicine.

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.

Dual-channel detection of viscosity and pH with a near-infrared fluorescent probe for cancer visualization.

Compared to ordinary cells, tumor cells have a unique microenvironment, characterized by high viscosity, low pH, high reactive oxygen species level and the overexpression of certain proteases. Therefore, viscosity and pH can be used as important parameters for visualizing cancer. We designed a spiro-oxazolidine compound (In-1) for the dual-channel detection of viscosity and pH, with the red channel for detecting viscosity and the blue channel for pH. Interestingly, In-1 can locate different organelles under different conditions. Under physiological conditions, In-1 efficiently targeted lysosomes and showed that the viscosity of lysosomes increases in cancer cells while the pH decreases, which can be used to distinguish and detect cancer cells and normal cells. When we treated HL-7702 cells with CCCP, the probe could effectively target the mitochondria, and the fluorescence intensity in the pH channel decreased. This indicates that In-1 can be used as a powerful tool to simultaneously monitor viscosity and pH in different organelles, and may have a guiding role in diseases caused by mitochondrial and lysosomal microenvironments.

A tracer-type fluorescent probe for imaging adenosine triphosphate under the stresses of hydrogen sulfide and hydrogen peroxide in living cells.

Adenosine triphosphate (ATP) is a direct energy source in cells and the core of the biochemical system, and is closely related to various metabolic activities in living organisms. Therefore, designing a simple and rapid ATP detection method is significant to study its physiological function. Herein, a dual-channel fluorescent probe RhB-NA for the in situ imaging of ATP in living cells was designed and synthesized. When ATP bound to RhB-NA, the spirolactam in rhodamine B was induced to open, resulting in a new fluorescence response at 589 nm. Notably, in cell imaging, the treatment of HeLa cells with exogenous H2O2 and H2S, which have certain effects on the mitochondria, confirmed that RhB-NA could detect fluctuations in ATP levels after the mitochondrial state was affected. We believe that RhB-NA has far-reaching significance for studying certain physiological diseases caused by abnormal ATP levels.

A fluorescent probe for monitoring Cys fluctuations in the oxidative stress environment simulated by Cu2+ or H2O2.

Redox balance is the core of holding the good physiological state of the body. Cysteine (Cys) is one of the important biomolecules, which plays an indispensable role in maintaining the body's redox homeostasis. The redox of organisms is mainly the result of the dynamic balance between reactive oxygen species (ROS) and biological reducing agents (such as Cys). Fluorescent probes have the advantages of simple operation, good specificity and high sensitivity, and have become a common tool for bio-sensing in complex systems. In this article, we designed a probe NF-O-SBD that can specifically detect Cys. The chlorine atom of NF-O-SBD was easily substituted by sulfhydryl as a reaction site. After the formation of sulfur substitution products, intramolecular rearrangement occurred and fluorescent signal was emitted in the yellow channel at 550 nm. It can be seen from the spectroscopy experiment that the content of Hcy in organisms (15 µM) basically did not cause significant fluorescence changes, Therefore, based on the practical application in biology, we further used NF-O-SBD to visualize endogenous and exogenous Cys in HepG-2 cells and zebrafish. Simultaneously, we used Cu2+ or H2O2 induction to simulate the oxidative stress environment of cells and zebrafish, under which the concentration variation of Cys was monitored.

Sound field reconstruction using block sparse Bayesian learning equivalent source method.

Nearfield acoustic holography based on the compressed sensing theory can realize the accurate reconstruction of sound fields with fewer measurement points on the premise that an appropriate sparse basis is obtained. However, for different types of sound sources, the appropriate sparse bases are diverse and should be constructed elaborately. In this paper, a block sparse Bayesian learning (SBL) equivalent source method is proposed for realizing the reconstruction of the sound fields radiated by different types of sources, including the spatially sparse sources, the spatially extended sources, and the mixed ones of the above two, without the elaborate construction of the sparse basis. The proposed method constructs a block sparse equivalent source model and promotes a block sparse solution by imposing a structured prior on the equivalent source model and estimating the posterior of the model by using the SBL, which can achieve the accurate reconstruction of the radiated sound fields of different types of sources simply by adjusting the block size. Numerical simulation and experimental results demonstrate the validity and superiority of the proposed method, and the effects of two key parameters, the block size, and sparsity pruning threshold value are investigated through simulations.

Magneto-optically reorientation-induced image reconstruction in bulk nematic liquid crystals.

We theoretically propose the magneto-optically reorientation-induced image reconstruction in bulk nematic liquid crystals (NLCs). The underlying signals are reinforced and recovered at the expense of scattering noise under reorientation-induced self-focusing nonlinearity. The intensity perturbation gain is derived and the numerical results are presented to show the response of NLC molecules to the diffusive images. The nonlinear image recovery is influenced by the input light intensity, the magnetic field direction, and the correlation length. The results suggest an alternative approach to detect noisy images and promote the application of NLCs in image processing.

A coumarin-based fluorescence sensor for rapid discrimination of cysteine/homocysteine and glutathione under dual excitation wavelengths.

Biological thiols (Cys, Hcy and GSH) are crucial biomolecules in living cells and play indispensable roles in maintaining the redox homeostasis of organisms. But due to their similar molecular structure, the development of effective tools for distinguishing two or three of them remains a great difficulty. Herein, we constructed a sensitive sensor (CB) by connecting the bifunctional fluorescent reagent with coumarin derivatives for simultaneous recognition of these three thiols through different pathways. Free CB had no fluorescence; however, with gradual addition of thiols, the chlorine unit was replaced by sulfhydryl. Furthermore, the intramolecular rearrangement occurred between the amino and sulfhydryl groups of Cys/Hcy and yellow fluorescence was observed at 570 nm. However, GSH with a large structure could not undergo intramolecular rearrangement, and green fluorescence was excited at 505 nm. In this way, Cys/Hcy and GSH can be detected distinctively. Under dual excitation wavelengths, CB exhibited high selectivity and fast response to the three thiols. Furthermore, CB was successfully applied to imaging endogenous and exogenous thiols in living cells and zebrafish, providing us with a reliable tool for thiols recognition.

Sulphide activity-dependent multicolor emission dye and its applications in in vivo imaging.

Reactive sulfur species (RSS) play pivotal roles in various pathological and physiological processes. There exists an intricate relevance in generation and metabolism among these substances. Although they are nucleophilic, there are still some differences in their reactivity. There are many methods to detect them by using reactive fluorescent probes, but the systematic study of their reactivity is still lacking. In our study, we designed a multiple reaction site fluorescent probe based on benzene conjugated benzopyrylium and NBD. The study revealed that besides both biothiols and hydrogen sulfide, sulfur dioxide (SO2) can cleave the ether bond. There are two reaction forms for GSH with low reactivity: cutting the ether bond and adding the conjugated double bond of benzopyrylium. Nevertheless, Cys/Hcy with higher activity can further rearrange with NBD after cutting the ether bond. In addition, SO2 can not only cleave the ether bond, but also continue to add the conjugated double bond of benzopyrylium. The above processes lead to multicolor emission of the probe, thus realizing the characteristic analysis of different sulfides. Thus the probe can be used for the detection of sulfide in mitochondria, and further for the imaging of sulfide in cells and zebrafish. This effective analysis method will provide a broad application prospect for practical applications.

High-Specific Fluorescence Probe for SO32- Detection and Bioimaging.

It is well known that sulfite (SO32-) plays an indispensable role in various physiological processes. Abnormal levels of SO32- can trigger a wide variety of diseases involving respiratory, nervous and cardiovascular systems. Hence, it is necessary to find an efficient approach for detection of SO32-. In this study, a pyrene derivative, (E)-4-(3-oxo-3-(pyren-1-yl)prop-1-en-1-yl)phenyl acrylate (PPA), was designed and synthesized for monitoring SO32-. The probe possessed simple synthetic steps, excellent anti-interference ability and specific response to SO32- in the presence of other substances. The reaction between PPA and SO32- was ascribed to Michael addition and the detection mechanism was confirmed by HRMS spectra analysis and FTIR analysis. Additionally, PPA responded linearly to detect SO32- within the rang of 0-100 µM. The limit of detection was calculated as low as 0.17 µM in accordance with the recommendation of IUPAC (CDL =3sb/m). Notably, PPA was further applied in biological imaging in HepG2 cells, which provided a possibility to monitor SO32- in vivo.

A Pyrene-Based Fluorescent Probe for Specific Detection of Cysteine and its Application in Living Cell.

Cysteine (Cys) is an essential amino acid in organism, which is transformed from methionine in vivo and participates in protein synthesis and cell redox process. Therefore, the detection of Cys is of great significance. In this work, a novel fluorescent probe, (E)-3-(2-chloroquinolin-3-yl)-1-(pyren-3-yl) prop-2-en-1-one (PAQ) was designed and synthesized to specifically detect Cys. The response mechanism of the reaction between PAQ and Cys was due to the addition reaction of Cys to α,ß-unsaturated ketone of PAQ. Interestingly, the addition of Cys induced significant fluorescence intensity enhancement at 462 nm. PAQ exhibited favorable sensing properties towards Cys such as the low limit of detection (0.27 µM) and fast response speed (2 min). In addition, PAQ displayed high selectivity and anti-interference ability toward Cys among various analytes. Notably, PAQ has been successfully used to image exogenous and endogenous Cys in HeLa cells.

Seroprevalence of Toxoplasma gondii and Neospora caninum in dairy cows in Hebei province, China.

Toxoplasma gondii (T. gondii) and Neospora caninum (N. caninum) are protozoan parasites that cause severe disease in animals and significant economic losses for farmers worldwide. Neospora caninum is considered to be a serious parasite for dairy cows, while T. gondii infection is a serious parasitic disease that can infect people and livestock. The aim of the present study was to investigate the seroprevalence of T. gondii and N. caninum in dairy cows in Hebei province, China. A total of 723 dairy cow sera samples from three regions in Hebei were analyzed by enzyme-linked immunosorbent assays (ELISA). The results revealed that 19.92% (144/723) of the individual serum samples were seropositive for T. gondii, 37.34% (270/723) of the individual serum samples were seropositive for N. caninum, and 8.7% (63/723) of the individual serum samples were seropositive for mixed infection. A higher seroprevalence of N. caninum was found in the present study, when compared to previous data. To the best of the author's knowledge, the present study is the first to detect T. gondii and N. caninum antibodies in the vast areas of Hebei province, China.

Separation of nonstationary sound fields based on the time-domain equivalent source method with single layer pressure-velocity measurements.

This paper proposes a sound field separation technique based on the time-domain equivalent source method with single layer pressure-velocity measurements to extract the nonstationary sound field radiated by the target source in a reverberant environment. This technique constructs a formulation that relates the pressures and particle velocities on a measurement surface to the strengths of time-domain equivalent sources arranged for modelling the outgoing and incoming waves. By solving the strengths of time-domain equivalent sources, the sounds coming from different sides of the measurement surface can be separated independently. In the proposed technique, the use of a time-domain equivalent source model allows the measurement surface to be arbitrarily shaped, thus providing the ability to analyze the arbitrarily shaped sources in a reverberant environment. Numerical simulations investigated the performance of the proposed technique when using different types of arrays, including planar, semi-cylindrical, and semi-spherical arrays, and an experiment with three loudspeakers located at two sides of the measurement surface was carried out to test the validity of the proposed technique. Both numerical and experimental results demonstrate that the proposed technique can remove the influence of disturbing sources in both time and space domains and separate out the target sound fields effectively.

Sensitivity analysis of acoustic eigenfrequencies by using a boundary element method.

This paper presents a boundary element-based scheme for the sensitivity analysis of acoustic eigenfrequencies of both interior and exterior acoustic systems. The nonlinear eigenvalue problem generated by the acoustic boundary element method is first reformulated into a generalized eigenvalue problem of reduced dimension through a contour integral approach. The sensitivity formulations for acoustic eigenfrequencies are then derived based on an adjoint method that uses both the right and left eigenvectors. The adaptive cross approximation in conjunction with the hierarchical matrices is used to reduce the solution burden of the boundary element systems. The Burton-Miller-type combined formulation is applied to shift the spurious eigenfrequencies and their sensitivities, and the strategies to identify the spurious results are suggested. Three numerical examples are used to verify the accuracy and applicability of the developed scheme.

Reconstruction of time-dependent forces acting on a vibrating structure from pressure measurements.

This paper proposes an approach to reconstruct the time-dependent forces acting on a vibrating structure from pressure measurements. In the approach, the pressures measured in the near field of the structure are related to the exciting forces at the reconstruction points by the transfer functions determined in an experimental way, whereupon the time-dependent forces can be reconstructed with these pressures as inputs. In the reconstruction process, an additional regularization with a mixed lp , q-norm term is introduced to resolve the ill-posed inverse problem, which is able to take advantage of the prior knowledge of space and time characteristics of the forces. A numerical simulation of reconstructing the time-dependent forces acting on a plate and two experiments of reconstructing the impact forces acting on a semi-cylindrical shell and an elliptically shaped structure are carried out. The results demonstrate the feasibility of the proposed approach for reconstructing the forces in both temporal and spatial domains from pressure measurements. The proposed approach provides a non-contact and real-time way to identify the locations of forces and reconstruct their time histories, which can be further used to reveal the mechanical cause of the radiated noise.

A New Strategy: Distinguishable Multi-substance Detection, Multiple Pathway Tracing Based on a New Site Constructed by the Reaction Process and Its Tumor Targeting.

In recent years, it has become a trend to employ organic molecular fluorescent probes with multireaction sites for the distinguishable detection and biological imaging of similar substances. However, the introduction of multireaction sites brought great challenges to organic synthesis, and at the same time, often destroyed the conjugated structure of the molecules, leading to an unsatisfactory fluorescence emission wavelength not conducive to practical application. As the eternal theme of life, metabolism goes on all the time. Metabolism is a series of ordered chemical reactions that occurs in the organism to maintain life. Chemical reactions in metabolism can be summarized as metabolic pathways. Simultaneous monitoring of different metabolic pathways of the same substance poses a lofty challenge to the probe. Here, we developed a new strategy: to construct new sites through the preliminary reactions between probes and some targets, which can be used to further distinguish among targets or detect their metabolites, so as to realize the simultaneous visualization tracer of multiple metabolic pathways. By intravenous injection, it revealed that the probe containing benzopyrylium ion can target tumors efficiently, and thiols are highly expressed in tumors compared to other tissues (heart, lung, kidney, liver, etc.). The consumption of thiols by the probe could not prevent tumor growth, suggesting that the tumor cure was not correlated with thiol concentration. The construction of new sites in the reaction process is a novel idea in the pursuit of multiple reaction sites, which will provide more effective tools for solving practical problems.

Heat Stroke in Cell Tissues Related to Sulfur Dioxide Level Is Precisely Monitored by Light-Controlled Fluorescent Probes.

Heat stroke (HS) can cause serious organism damage or even death. Early understanding of the mechanism of heat cytotoxicity can prevent or treat heat stroke related diseases. In this work, probe Ly-NT-SP was synthesized, characterized, and used for sulfur dioxide (SO2) detection in lysosomes. PBS solutions of probe Ly-NT-SP at pH 5.0 present a marked broad emission band in the green zone (535 nm). After UV irradiation, the spiropyran group in Ly-NT-SP isomerizes to the merocyanine form (Ly-NT-MR), which presented a weak red-shifted emission at 630 nm. In addition, photocontrolled isomerization of Ly-NT-SP to Ly-NT-MR generated a C═C-C═N+ fragment able to react, through a Michael addition, with SO2 to yield a highly emissive adduct with a marked fluorescence in the green channel (535 nm). In vitro studies showed a remarkable selectivity of photoactivated Ly-NT-MR to SO2 with a limit of detection as low as 4.7 µM. MTT viability assays demonstrated that the Ly-NT-SP is nontoxic to HeLa cells and can be used to detect SO2 in lysosomes. Taking advantage of this, the sensor is successfully applied to image increasing SO2 values in lysosomes during heat shock for the first time. Moreover, we also confirmed that the increased SO2 can protect the small intestine against damage induced by heat shock through regulating oxidative stress in cells and mice.