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.

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.

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).

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.

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 are shown.

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.

Synthesis and herbicidal activity of novel pyrazole aromatic ketone analogs as HPPD inhibitor.

Background: 4-Hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.

Synthesis and in vivo fungicidal activity of some new quinoline derivatives against rice blast.

Background: Quinoline derivatives possess excellent fungicidal activity against rice blast, but quinoline derivatives have not been thoroughly explored as fungicides. In the process of designing new fungicides, the 1,1,1,2,3,3,3-heptafluoropropan-2-yl group was introduced in order to find new structure quinoline derivatives.

Results: Seventeen new quinoline derivatives containing 1,1,1,2,3,3,3-heptafluoropropan-2-yl moiety were designed and synthesised.

Synthesis, nematocidal activity and SAR study of novel difluoromethylpyrazole carboxamide derivatives containing flexible alkyl chain moieties.

A series of novel difluoromethylpyrazole carboxamides derivatives were synthesized by introduction of flexible alkyl chain. Nematicidal bioassay results showed that some of them exhibited good control efficacy against M. incognita, which indicated that these difluoromethylpyrazole carboxamides derivatives might be potential novel lead compounds for discovery new nematicides.

Synthesis, nematocidal activity and docking study of novel chiral 1-(3-chloropyridin-2-yl)-3-(trifluoromethyl)-1H-pyrazole-4-carboxamide derivatives.

A series of novel chiral fluorinated pyrazole carboxamides derivatives were designed and synthesized. All these title compounds were confirmed by NMR and MS. The primarily nematocidal activity results indicated that some of them exhibited good control efficacy against the tomato root-knot nematode disease caused by Meloidogyne incognita.

The evaluation of the association between the metabolic syndrome and tumor grade and stage of bladder cancer in a Chinese population.

Objective: The objective of this article was to summarize the relationship between some components of metabolic syndrome (MetS) and the histopathologic findings in bladder cancer in a Chinese population.

Methods: We retrospectively analyzed data of 323 patients from the Department of Urology, Second Hospital of Tianjin Medical University between January 2012 and January 2014. All the patients were diagnosed with bladder cancer for the first time.

Orbital-type trapping of elastic Lamb waves.

The interaction of laser-generated Lamb waves propagating in a plate with a sharp-angle conical hole was studied experimentally and numerically. Part of the energy of the incident wave is trapped within the conic area in two ways: the antisymmetric Lamb wave orbiting the center of the hole and the wave localized at the acute edge. Parameters and conditions for optimal conversion of the incident wave into the trapped modes were studied in this work.

Study of underwater laser propulsion using different target materials.

In order to investigate the influence of target materials, including aluminum (Al), titanium (Ti) and copper (Cu), on underwater laser propulsion, the analytical formula of the target momentum IT is deduced from the enhanced coupling theory of laser propulsion in atmosphere with transparent overlay metal target. The high-speed photography method and numerical simulation are employed to verify the IT model. It is shown that the enhanced coupling theory, which was developed originally for laser propulsion in atmosphere, is also applicable to underwater laser propulsion with metal targets.

Anterolateral minithoracotomy versus median sternotomy for mitral valve disease: a meta-analysis.

Objective: Mitral valve disease tends to be treated with anterolateral minithoracotomy (ALMT) rather than median sternotomy (MS), as ALMT uses progressively smaller incisions to promote better cosmetic outcomes. This meta-analysis quantifies the effects of ALMT on surgical parameters and post-operative outcomes compared with MS.

Methods: One randomized controlled study and four case-control studies, published in English from January 1996 to January 2013, were identified and evaluated.

Formation and dynamics of a toroidal bubble during laser propelling a cavity object in water.

We captured stable self-oscillations of a toroidal bubble moving away from a laser propelled cavity object in water using a high-speed imaging system. The entire laser propelling process generates a hemispherical bubble, two toroidal bubbles, and a microbubble cluster. The hemispherical bubble is formed by laser breakdown in water.

Evaluation of third-order elastic constants using laser-generated multi-type ultrasound for isotropic materials.

Within the linear elasticity approximation the speed of a small-amplitude sound in conventional linear elasticity is determined only by the second order elastic (SOE) constants and the density of the medium. Subjecting the conveying solid to a static strain of a sufficient magnitude introduces the third-order elastic (TOE) constants in the equation of the sound speed. In this work we applied a homogeneous isotropic deformation caused by a thermal expansion of an aluminum alloy sample.

Numerical simulation of the influence of the elastic modulus of a tumor on laser-induced ultrasonics in soft tissue.

The influence of the elastic modulus of a tumor (EMT) on the laser-generated thermoelastic force source and ultrasound waves are investigated by using the finite element method. Taking into account the effects of thermal diffusion, optical penetration, and finite duration of laser pulse, the transient temperature distribution is obtained. Applying this temperature field to structure analyses as thermal loading, the thermoelastic stress field and laser-induced ultrasound wave in soft tissues are obtained.

[Progress in study of the structure, catalytic mechanism and inhibitors of aromatase].

Aromatase is a key enzyme responsible for in vivo estrogen biosynthesis. Inhibition of the activity of the aromatase has become an alterative way for treatment of breast cancer. In this review, the structure and catalytic mechanism of the aromatase is briefly introduced followed by thorough review of the progress in the study of the steroidal and non-steroidal aromatase inhibitors.

Probing of laser-induced crack modulation by laser-monitored surface waves and surface skimming bulk waves.

All-optical monitoring of the nonlinear motion of a surface-breaking crack is reported. Crack closing is induced by quasi-continuous laser heating, while Rayleigh surface acoustic pulses and bulk longitudinal surface skimming acoustic pulses are also generated and detected by lasers. By exploiting the strong dependence of the acoustic pulses reflection and transmission efficiency on the state-open or closed-of the contacts between the crack faces, the parametric modulation of ultrasonic pulses is achieved.

[Identification of protoporphyrin IX fluorescence spectrum in human blood serum by biorthogonal spline wavelet].

For the low content and weak fluorescence intensity, usually presenting shoulder peaks, it is often hard to locate protoporphyrin IX and identify its fluorescence intensity in human blood serum. Biorthogonal spline wavelet may work for the identification of its weak signal Superimposing protoporphyrin IX fluorescence signal on the background of blood serum spectrum, a series of varied fluorescence spectra of them can be obtained. The protoporphyrin IX fluorescence signal from blood serum background is separated and the fluorescence spectrum can be divided into corresponding discrete approximate signals (a1-a7) and discrete details signals (d1-d7) by biorthogonal spline wavelet bior 5.

[Fluorescence spectrum analysis system for protoporphyrin IX in serum based on wavelet transform].

Protoporphyrin IX is an important kind of organic compound for vital movement, and can be used as the sign of tumour blood. Human protoporphyrin IX content in serum is very low, and affected by various factors. The serum fluorescence spectrum analysis system based on wavelet transform was used to discriminated the protoporphyrin IX weak signals.

[Vascular effect of extract from mulberry leaves and underlying mechanism].

Objective: To investigate the vascular activity of extract from mulberry leaves (EML) on rat thoracic aorta and the underlying mechanism.

Methods: Isolated thoracic rings of Sprague-Dawley rats were mounted on the organ bath and the tension of the vessel was recorded.

Result: (1) EML produced a concentration-dependent vasorelaxation of aorta preconstricted by high K(+) (60 mmol/L) or 10(-6) mol/L phenylephrine (PE) in endothelium-intact and endothelium-denuded arteries.

Investigation on utilizing laser speckle velocimetry to measure the velocities of nanoparticles in nanofluids.

Laser speckle velocimetry (LSV) is presented to measure the velocities of nanoparticles in nanofluids and its feasibility is verified in this paper. An optical scattering model of a single nanoparticle is developed and numerical computations are done to simulate the formation of the speckles by the addition of the complex amplitudes of the scattering lights from multiple nanoparticles. Then relative experiments are done to form speckles when nanofluids are illuminated by a laser beam.