Experimental study on opto-acoustic nonlinear frequency-mixing technique with separated basic temperature.

Different from the traditional frequency-mixing technique which employs a contacting transducer, the laser-induced acoustic nonlinear frequency-mixing detection technique utilizes a laser source to instigate crack motion and generate acoustic waves. Thus, apart from the temperature oscillation induced by the pump laser, the "basic temperature" originating from the probe laser can also influence the crack. This additional variable complicates the contact state of the crack, yielding a more diverse range of nonlinear acoustic signal attributes. In light of this, our study enhances the conventional opto-acoustic nonlinear frequency mixing experimental setup by integrating an independent heating laser beam. This modification isolates the impact of the "basic temperature" on crack width while also dialing down the probe laser power to mitigate its thermal effects. To amplify the sensitivity of crack detection, we deliberated on the optimal laser source parameters for this setup. Consequently, our revamped system, paired with fine-tuned parameters, captures nonlinear acoustic signals with an enriched feature set. This investigation can provide support for the non-contact opto-acoustic nonlinear frequency mixing technique in the detection and evaluation of micro-cracks.

Study of thermal effects induced by the high-frequency probing laser in nonlinear opto-acoustic frequency-mixing technique.

Photo-thermal modulation-based nonlinear opto-acoustic frequency-mixing technique is an effective method for detecting micro-cracks. When using this technique for micro-crack detection, the selection of laser source parameters is particularly crucial. Compared to traditional piezo-transducer-based mixing techniques, the characteristic of using a laser as the detection source is the presence of thermal effects. The thermal effect caused by laser irradiation on the sample surface can not only generate acoustic waves but also affect the crack state, thus influencing nonlinear signals. In this paper, an experimental setup using photo-thermal modulation-based nonlinear opto-acoustic frequency-mixing technique has been set up to investigate the thermal effects of the probe laser source. In addition, a corresponding physical model has been established to discuss the physical mechanisms revealed by the experimental results. This study provides a basis for selecting appropriate probe source parameters and scanning positions of laser sources when detecting micro-cracks using the photo-thermal modulation-based nonlinear opto-acoustic frequency-mixing technique.

Distribution characteristics of microorganisms in sediments of Dagu River and their biological indicator function for evaluating eco-environmental quality of rural river.

The microorganisms in sediments play a crucial role in biogeochemical cycle processes, and numerous studies have shown that microbial community is closely related to environmental factors. However, the usability of sediment microorganisms to evaluate the eco-environment quality of rural rivers has not been adequately explored. This study investigated the distribution characteristics and response of sediment microorganisms to environmental parameters and benthic organisms. Based on the environmental parameters and benthic community indices, the 12 stations were divided into high-polluted group A, moderate-polluted group B and low-polluted group C. Station DG01 and DG02 in group A had the highest level of As and Ni pollution and nutrient concentration, and DG09 in group A had the lowest benthic diversity. Correspondingly, group A had the lowest abundance of Proteobacteria, which has a higher requirement for the environment than Planctomycetes. Group B had the highest sulfide level (97.45 mg/kg), and bacteria (Thiobacillus, Sulfurisoma and Sulfuritalea) with genes involved in sulfur cycling were more enriched in this group. Group C had the lowest level of total nitrogen (243.36 mg/kg), and Rhodanobacteraceae in Xanthomonadales might be a key bioindicator for low nitrogen. In addition, Chlorophyta was found to be more susceptible to heavy metals, and moreover co-occurrence networks showed that microeukaryotes were more sensitive to heavy metal pollution compared to benthic animals and prokaryotes. Therefore, this study suggested that benthic microorganisms especially microeukaryotes could be used as good indicators for evaluating the eco-environmental quality of rural rivers.

Rapid observation of dispersion curves in system-on-chip devices.

We have developed a rapid detection instrument to characterize the behavior of light on the surface of devices during light-matter interactions. The equipment enables the non-destructive and real-time observations of the dispersion curves for microstructures, providing the basis for a large number of new planar photonic chip applications. The method is based on the traditional prismatic reflection and makes full use of the grating dispersion capabilities, enabling simultaneous multi-wavelength and multi-angle reflectance measurements over a wide range. This method is beneficial for designing new microstructure devices and brings convenience to delicate microstructure processing. The instruments do not require any mechanical scanning, allowing for rapid acquisition, and the integrated and reusable optics make them easily miniaturized. Additionally, the functionalized design allows for spectral analysis applications, such as far-field spectral measurements. The instrument can also be easily integrated into established microscopic imaging systems, extending their observational characterization capabilities as well as accomplishing dynamic monitoring in proven system-on-a-chip devices.

Measurement of temperature dependent shear modulus using frequency dependent SAWs ToF delay in laser-induced temperature gradient.

Phase velocity of surface acoustic waves(SAWs) is frequency dependent when propagate on medium with inhomogeneous elasticity over depth. In this work, frequency dependent Time-of-Flight (ToF) variation of SAWs induced by a local and dynamic heating was applied for measurement of temperature dependent shear modulus. Laser-generated broad-band SAWs propagated through the material with elastic properties and density modified by dynamic inhomogeneous temperature field induced by a millisecond laser heating. Sample with spatial dependent material properties introduces phase velocity dispersion in the SAW propagation. As consequence, ToF of SAW becomes frequency dependent. Frequency dependent ToF variation curves at two time instants respected to laser heating were measured by time-frequency analysis together with a differential technique. Free fitted parameters, temperature dependent shear modulus and surface temperature distribution were evaluated by solving the inverse problem by fitting the experimental ToF variation curves into the theoretical ones by means of the differential evolution method. The inversed temperature dependent parameter of shear modulus of Ti-6Al-4V alloy was in good agreement with literature value.

The dynamic cellular landscape of grafts with acute rejection after heart transplantation.

BACKGROUND: Acute cellular rejection (ACR) is a major barrier to the long-term survival of cardiac allografts. Although immune cells are well known to play critical roles in ACR, the dynamic cellular landscape of allografts with ACR remains obscure. METHODS: Single-cell RNA sequencing (scRNA-seq) was carried out for mouse cardiac allografts with ACR. Bioinformatic analysis was performed, and subsequent transplant experiments were conducted to validate the findings. RESULTS: Despite an overall large depletion of cardiac fibroblasts (CFBs), highly expanded cytotoxic T lymphocytes and a CXCL10+Gbp2+ subcluster of CFBs were enriched within grafts at the late stage. CXCL10+Gbp2+ CFBs featured strong interferon responsiveness and high expression of chemokines and major histocompatibility complex molecules, implying their involvement in the recruitment and activation of immune cells. Cell‒cell communication analysis revealed that CXCL9/CXCL10-CXCR3 might contribute to regulating CXCL10+Gbp2+ CFB-induced chemotaxis and immune cell recruitment. In vivo transplant studies revealed the therapeutic potential of CXCR3 antagonism in transplant rejection. CONCLUSIONS: The findings of our study unveiled a novel CFB subcluster that might mediate acute cardiac rejection. Targeting CXCR3 could prolong allograft survival.

Synthesis, crystal structure, herbicidal activity and mode of action of new cyclopropane-1,1-dicarboxylic acid analogues.

A new series of cyclopropane-1,1-dicarboxylic (CPD) acid analogues were designed and synthesized. CPD is an inhibitor of ketol-acid reductoisomerase (KARI), an enzyme of the branched chain amino acid pathway in plants. The structures of CPD analogues were characterized by 1H NMR and HRMS. The structure of N,N'-bis(4-(tert-butyl)phenyl)cyclopropane-1,1-dicarboxamide was further elucidated by X-ray diffraction. The herbicidal activities of these compounds were tested against lettuce (Lactuca sativa) and bentgrass (Agrostis stolonifera). Most of these compounds exhibited low herbicidal activity against both plant species. Among them, N,N'-bis(2-ethylphenyl)cyclopropane-1,1-dicarboxamide displayed moderate activity against bentgrass. Inhibition of KARI activity by the CPD analogues was also assessed experimentally and by molecular docking simulation with results supporting inhibition of KARI as their mode of action. These results provide the basis for design of more effective KARI inhibitors.

Transcoronary sinus repair of a severely dilated and tortuous right coronary artery fistulized to coronary sinus complicated with tricuspid valve insufficiency.

BACKGROUND: Right coronary artery (RCA) fistulized to the coronary sinus is rare condition in adult cardiac anomalies, and the management and operative indication are controversial. CASE PRESENTATION: We describe the case of a 45-year female patient who presented with exertional dyspnea, accompanied by intermitted lower limbs and facial edema. She was diagnosed with severe tricuspid regurgitation second to a severely dilated RCA fistulized to the coronary sinus. After multidisciplinary discussion, she underwent surgery through routine medium sternotomy, the right atrium was opened under cardiopulmonary bypass. The coronary arteriovenous fistula from the distal portion of RC to a severely enlarged coronary sinus was found. Trans-coronary sinus closure of the fistula was performed with continuous stitching and a tricuspid ring annuloplasty was done. The patient recovered uneventful post operation. CONCLUSION: According to current literatures, surgical treatment was adopted for this case, instead of endovascular intervention. The optimal approach for these cases should consider the heart's anatomical characteristics. But we need to be aware of the occurrence of myocardial infarction and tricuspid regurgitation in the early and late stage after operation.

Dynamic moist air monitor in a micro area with extremely high figure-of-merit.

In the rapidly changing moisture air, conventional relative humidity (RH) sensors are often difficult to respond in time and accurately due to the limitation of flow rate and non-uniform airflow distribution. In this study, we numerically demonstrate that humidity changes on micro-zones can be monitored in real time using a Bloch surface wave (BSW) ubiquitous in one-dimensional photonic crystals (1DPC). This phenomenon can be observed by leakage radiation microscope (LRM). After theoretically deriving the angular resolution limit of LRM, we obtained the minimum BSW angular change on a practical scheme that can be observed in the momentum space to complete the detection, and realized the dynamic real-time monitoring of small-scale humidity change in experiment for the first time. This monitoring method has extremely high figure of merit (FOM) without hysteresis, which can be used in humidity sensing and refractive index sensing as well as the research on turbulence.

Interaction between the mid-infrared continuous wave laser with a center wavelength of 3.8†µm and fused silica.

The absorption coefficient of fused silica for a mid-infrared (IR) laser is higher than that for a near-IR laser, but smaller than that for a far-IR laser. Therefore, the energy coupling efficiency of the mid-IR laser is higher than that for the near-IR laser, while the penetration depth is higher than that for the far-IR laser. Thus, the mid-IR laser is highly efficient in mitigating damage growth. In this study, a deuterium fluoride (DF) laser with a center wavelength of 3.8 µm was used to interact with fused silica. The temperature variation, changes in the reflected and transmitted intensities of the probe light incident on the laser irradiation area, and the vaporization and melting sputtering process were analyzed. The results demonstrate that when the laser intensity was low (<1.2 kW/cm2), no significant melting was observed, and the reflection and transmission properties gradually recovered after the end of the laser irradiation process. With a further increase in the laser intensity, the sample gradually melted and vaporized. At a laser intensity above 5.1 kW/cm2, the temperature of the sample increased rapidly and vapors in huge quantity evaporated from the surface of the sample. Moreover, when the laser intensity was increased to 9.5 kW/cm2, the sample melted and an intense melting sputtering process was observed, and the sample was melted through.

A Novel Credible Carbon Footprint Traceability System for Low Carbon Economy Using Blockchain Technology.

To achieve the goal of carbon neutrality, many countries have established regional carbon emission trading markets and tried to build a low-carbon economic system. At present, the implementation of carbon emission trading and low-carbon economic systems faces many challenges such as manipulation, corruption, opacity, lack of trust, and lack of data tracking means. The application of blockchain technology can perfectly solve the above problems. However, the data recorded on a blockchain are often multi-type and heterogeneous, and users at different levels such as regulators, enterprises, and consumers have different requirements for data types and granularity. This requires a quick and trustworthy method for monitoring the carbon footprint of enterprises and products. In this paper, the carbon footprint traceability of enterprises and products is taken as an application scenario, and the distributed traceability concept of "traceability off the chain and verification on the chain" is adopted. By reconstructing the pointer of the file structure of the distributed storage, an interactive traceability structure supporting type filtering is constructed, which enables fast retrieval and locating of carbon emission data in the mixed data on the chain. The experimental results show that using the interactive traceability structure that supports type filtering for traceability not only releases the computing power of full nodes but also greatly improves the traceability efficiency of the long-span transaction chain. The proposed carbon footprint traceability system can rapidly trace and track data on an enterprise's and a product's carbon footprint, as well as meet the needs of users at all levels for traceability. It also offers more advantages when handling large amounts of data requests.

Laser ultrasonic loading and optical interference detection of closed cracks in K9 glass.

The traditional optical detection method has a limitation in detecting closed cracks in optical elements. In this Letter, a novel, to the best of our knowledge, method has been developed for the detection of closed cracks in transparent samples. Firstly, behaviors of closed cracks under ultrasonic waves loading are demonstrated through the finite-element method (FEM). Simulation results show that the crack can be opened by the laser ultrasonic shear wave (S-wave). Then, a Mach-Zehnder interferometer system is experimentally established to detect closed cracks under ultrasonic waves loading in the sample. It is demonstrated that closed cracks which cannot be detected by interferometry become visible in interferogram images under ultrasonic waves loading. The width of the opened crack can also be quantitatively estimated. Thus the method would be a promising approach to detect initially closed cracks in optical elements.

Multi-mode laser-ultrasound imaging using Time-domain Synthetic Aperture Focusing Technique (T-SAFT).

The Synthetic Aperture Focusing Technique (SAFT) is an imaging algorithm used in laser ultrasonics (LU) to visualise the appearance of defects. However, ultrasound excited by a pulsed laser has the characteristics of wide bandwidth and multi-mode directivity patterns, leading to common problems in the SAFT process, such as low utilisation of ultrasound information and possible artefacts. To solve these problems, a Multi-mode Time-domain SAFT (MMT-SAFT) algorithm is proposed in this paper. The influence of ultrasonic directivity is discussed according to the imaging depth range, and imaging with multiple LU modes is performed to reduce artefacts. Simulations and experimental results prove the feasibility of the MMT-SAFT algorithm, which not only presents a clearer image of the upper part of defects but also improves image quality compared with time-domain SAFT using a single ultrasonic mode. The proposed technique can provide feasible directions for laser ultrasonic defect imaging.

Visualizing Commognitive Responsibility Shift in Collaborative Problem-Solving During Computer-Supported One-to-One Math Tutoring.

The aim of this study is to use a commognitive responsibility framework to visualize responsibility shift in collaborative problem solving (CPS) during computer-supported one-to-one tutoring. Commognitive responsibility shift means that individuals' cognitive responsibility shift can be reflected by the discourse in communication. For our sample, we chose a 15-year-old Chinese boy and his mathematics teacher with 6 years of teaching experience, both of whom have experienced computer-supported learning and teaching mathematics, respectively. We collected four tutoring videos (each 60-90 min; in total, more than 330 min) online, and a 45-min interview video from the teacher. We found that the third type of commognitive responsibility shift in both the teacher's and student's CPS behavior online is not only teacher-student comparison but also alternating-led, which includes teacher-student-led (TS) and student-teacher-led (ST).

Hypoxia-inducible factor-1α inhibition augments efficacy of programmed cell death 1 antibody in murine prostatic cancer models.

This study was designed to explore whether hypoxia-inducible factor-1α (HIF-1α) inhibitor could enhance immunotherapy efficacy in prostate cancer. Western blot was used to detect the expression of HIF-1α in the tumor and peritumor tissues from prostate cancer patients. The analysis from Cancer Genome Atlas database was used to show an association between HIF-1α expression and survival rate in prostate cancer patients. Murine prostate cell-derived xenograft (CDX) model was set up in both nude mice and BALB/c mice to observe the therapeutic effect of HIF-1α inhibitor IDF-11774. Protein expression of HIF-1α, as well as changes in the immune microenvironment, was detected. Moreover, the synergistic antitumor effect of IDF-11774 and PD-1 antibody was detected in another murine prostate cancer model. HIF-1α was found to have higher expression in prostate cancer tumor tissue than in peritumor tissue, and the expression level was negatively correlated with survival rate (P = 0.0157). HIF-1α inhibitor IDF-11774 reduced tumor volume and exhibited better efficacy in BALB/c mouse model (P < 0.0001) with normal immune system, with the same suppression level against HIF-1α. HIF-1α inhibitor reduced CD45+CD11b+Gr-1+ myeloid-derived suppressor cells (P = 0.0027) and CD45+ CD11b+F4/80+CD206hi M2 macrophages (P = 0.0059) but increased the abundance of CD45+CD3+CD8+ T cells (P = 0.0002) and CD45+CD3+CD4+ T cells (P = 0.0001) in tumor-infiltrating immune cells. The same synergistic effect was observed in RM-1 murine prostate CDX tumor model. HIF-1α inhibition augmented the antitumor efficacy of immune checkpoint inhibitor PD-1 antibody in murine prostate cancer models, probably through modulating the immunosuppressive microenvironment.

Data-Driven Dynamic Adjustment and Optimization Model of Emergency Logistics Network in Public Health.

BACKGROUND AND AIM: In the long-term prevention of the COVID-19 pandemic, parameters may change frequently for various reasons, such as the emergence of mutant strains and changes in government policies. These changes will affect the efficiency of the current emergency logistics network. Public health emergencies have typical unstructured characteristics such as blurred transmission boundaries and dynamic time-varying scenarios, thus requiring continuous adjustment of emergency logistics network to adapt to the actual situation and make a better rescue. PRACTICAL SIGNIFICANCE: The infectivity of public health emergencies has shown a tendency that it first increased and then decreased in the initial decision-making cycle, and finally reached the lowest point in a certain decision-making cycle. This suggests that the number of patients will peak at some point in the cycle, after which the public health emergency will then be brought under control and be resolved. Therefore, in the design of emergency logistics network, the infectious ability of public health emergencies should be fully considered (ie, the prediction of the number of susceptible population should be based on the real-time change of the infectious ability of public health emergencies), so as to make the emergency logistics network more reasonable. METHODS: In this paper, we build a data-driven dynamic adjustment and optimization model for the decision-making framework with an innovative emergency logistics network in this paper. The proposed model divides the response time to emergency into several consecutive decision-making cycles, and each of them contains four repetitive steps: (1) analysis of public health emergency transmission; (2) design of emergency logistics network; (3) data collection and processing; (4) adjustment and update of parameters. RESULTS: The result of the experiment shows that dynamic adjustment and update of parameters help to improve the accuracy of describing the evolution of public health emergency transmission. The model successively transforms the public health emergency response into the co-evolution of data learning and optimal allocation of resources. CONCLUSION: Based on the above results, it is concluded that the model we designed in this paper can provide multiple real-time and effective suggestions for policy adjustment in public health emergency management. When responding to other emergencies, our model can offer helpful decision-making references.

Mathematical modeling and optimal control of the COVID-19 dynamics.

We are considering a new COVID-19 model with an optimal control analysis when vaccination is present. Firstly, we formulate the vaccine-free model and present the associated mathematical results involved. Stability results for R 0 < 1 are shown. In addition, we frame the model with the vaccination class. We look at the mathematical results with the details of the vaccine model. Additionally, we are considering setting controls to minimize infection spread and control. We consider four different controls, such as prevention, vaccination control, rapid screening of people in the exposed category, and people who are identified as infected without screening. Using the suggested controls, we develop an optimal control model and derive mathematical results from it. In addition, the mathematical model with control and without control is resolved by the forward-backward Runge-Kutta method and presents the results graphically. The results obtained through optimal control suggest that controls can be useful for minimizing infected individuals and improving population health.

Non-destructive laser-ultrasonic Synthetic Aperture Focusing Technique (SAFT) for 3D visualization of defects.

The Laser Ultrasonic (LU) technique has been widely studied. Detected ultrasonic signals can be further processed using Synthetic Aperture Focusing Techniques (SAFTs), to detect and image internal defects. LU-based SAFT in frequency-domain (F-SAFT) is developed to visualize horizontal hole-type defects in aluminum. Bulk acoustic waves are non-destructively generated by irradiating a laser line-source, and detected using a laser Doppler vibrometer at a point away from the generation. The influence of this non-coincident generation-detection on the equivalent acoustic velocity used in the algorithm is studied via velocity mappings. Because the wide-band generation characteristic of the LU technique, frequency range selections in acoustic wave signals are implemented to increase Signal-to-Noise Ratio (SNR) and reconstruction speed. Results indicate that by using the LU F-SAFT algorithm, and incorporating optimizations such as velocity mapping and frequency range selection, small defects can be visualized in 3D with corrected locations and improved image quality.

Quercetin Downregulates Cyclooxygenase-2 Expression and HIF-1α/VEGF Signaling-Related Angiogenesis in a Mouse Model of Abdominal Aortic Aneurysm.

OBJECTIVE: Abdominal aortic aneurysm (AAA) development has been characterized by increased expression of vascular endothelial growth factor (VEGF), which contributes to angiogenesis via cyclooxygenase-2 (COX-2). Quercetin, one of the most common and well-researched flavonoids and abundant in vegetables and fruits, has beneficial effects in inhibiting angiogenesis. This study investigated the antiangiogenic effects of quercetin on experimental aneurysms. METHODS: We utilized the in vivo AAA mouse model induced by the periaortic application of CaCl2 to examine the effectiveness of quercetin in blocking angiogenesis. Quercetin was administered at 60 mg/kg once daily on the day of the AAA induction and then continued for 6 weeks. Celecoxib, a selective COX-2 inhibitor, was used as the positive control. RESULTS: Our results demonstrated that quercetin significantly attenuated aneurysm growth in AAA mice and medial neovascularization. Accordingly, quercetin decreased the expression of proangiogenic mediators, including VEGF-A, intercellular adhesion molecule-1, vascular cell adhesion molecule 1, and vascular endothelial cadherin. Quercetin treatment also inhibited the expression of COX-2 and hypoxia-inducible factor 1α (HIF-1α). It was also found that quercetin-3-glucuronide, a major quercetin metabolite, downregulated the expression of COX-2, HIF-1α, VEGF-A, and matrix metalloproteinase activities in aortic vascular smooth muscle cells isolated from AAA mice. CONCLUSION: Quercetin attenuates neovascularization during AAA growth, and this effect is mediated via the inhibition of COX-2, which decreases HIF-1α/VEGF signaling-related angiogenesis.

Small cell carcinoma of the upper urinary tract and factors associated with progress survival: a systematic review and pooled analysis.

INTRODUCTION: Little is known about small cell carcinoma of the upper urinary tract (UUT-SCC), the aim of this study is to identify the risk factors in relation to survival of patients with UUT-SCC. EVIDENCE ACQUISITION: Literature search on UUT-SCC was performed in databases including MEDLINE, EMBASE, Wangfang, and CNKI. Studies were eligible for inclusion if outcomes of patients with histopathologically confirmed UUT-SCC were reported. The relevant data on clinic, pathology, and therapy were collected. Progress survival was evaluated using the Cox regression model with the robust sandwich estimates of the covariance matrix. EVIDENCE SYNTHESIS: There were 55 eligible publications identified, contributing 76 patients in total. The median of overall survival (OS) was 14 months. In univariable analyses, pathological stage and platinum-based chemotherapy regimen were associated with OS (pT3-pT4 versus pT1-pT2, HR=3.228, P=0.005; other chemotherapies versus platinum-based, HR=6.249, P=0.035). The median of cancer-specific survival (CSS) was 15 months. In univariable analyses, pathological stage and platinum-based chemotherapy regimen were associated with CCS (pT3-pT4 versus pT1-pT2, HR=3.332, P=0.004; non-platinum based versus platinum-based, HR=7.784, P=0.025). CONCLUSIONS: In multivariable analyses, no variables were associated with OS and CSS. UUT-SCC is a rare tumor characterized by an aggressive clinical course. Pathological stage and platinum-based chemotherapy regimen are the most important factors related to OS and CSS.