Determination of chlorantraniliprole and penoxsulam residues in rice by QuEChERS-UPLC-MS/MS

Objective: To establish a new QuEChERS-ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the detection of chlorantraniliprole and penoxsulam residues in rice. Methods: After the sample was extracted with 0.2% formic acid-acetonitrile, purified with N-propylethylenediamine (PSA) and graphitized carbon black (GCB) packing, 0.2% formic acid water and acetonitrile were used as mobile phases for gradient elution, and then subjected to C18 chromatography. UPLC-MS/MS was used to column separation and determination. Results: The limits of quantification (LOQ) of chlorantraniliprole and penoxsulam were both 0.004 mg/kg, and the method detection limits (LOD) were both 0.001 mg/kg. Chlorantraniliprole and penoxsulam had a good linear relationship in the range of 0.002~0.5 mg/L, and their coefficient was greater than 0.993. At the addition levels of 0.05, 0.1, and 0.5 mg/kg, the average recovery rates of chlorantraniliprole and penoxsulam were 86% to 110% with the relative standard deviations (RSD) of 1.5% to 6.1%. Conclusion: This method is efficient and simple, has good stability and high sensitivity, and is suitable for the detection of chlorantraniliprole and penoxsulam in rice

Irisin attenuates angiotensin II-induced atrial fibrillation and atrial fibrosis via LOXL2 and TGFβ1/Smad2/3 signaling pathways

Objective(s): Irisin was reported as a cardioprotective and anti-oxidative effector, while the effect on atrial fibrosis is unknown. The current research examined irisin’s function in atrial fibrillation (AF); atrial fibrosis brought on by Ang II can be suppressed, thus lessening the risk of developing AF. Materials and Methods: 246 individuals were enrolled in the present case-control study. Chinese AF patients (n=126), 83 of whom were paroxysmal AF (PAF), 43 patients with persistent AF (PeAF), and 120 healthy controls. Saline or Ang II (2.0 mg/kg/day) was subcutaneously injected into healthy male C57BL/6 mice for four weeks. Once daily for four weeks, intraperitoneal injections of exogenous irisin (500 g/kg/day) were administered. Results: In comparison to PAF patients and healthy controls (all P<0.05), PeAF patients had significantly higher rates of heart failure (HF), large left atrial size (LAD), hypertrophic protein B-type natriuretic peptide (BNP), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), C-terminal telopeptide of type I collagen (CTX-I), and transforming growth factor beta-1 (TGF-β1), while superoxide dismutase (SOD) level was low. Expression of irisin was decreased in AF patients’ serum and Ang II-infused mice. Exogenous irisin dramatically reduced apoptosis, atrial fibrosis, atrial inflammation, and the susceptibility to AF caused by Ang II. In the atrial tissue, irisin inhibited Ang II-induced fibroblast transdifferentiation, LOXL2, TGF-β1, collagen production, and phosphorylation of Smad2/3. Conclusion: The study results speculated that irisin could be a potential AF target, and it inhibited atrial fibrosis and significantly impaired increased AF susceptibility through inactivation of LOXL2 and the TGF-β/Smad pathway

Integrated IVUS-OCT Imaging for Atherosclerotic Plaque Characterization.

For the diagnosis of atherosclerosis, biomedical imaging techniques such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have been developed. The combined use of IVUS and OCT is hypothesized to remarkably increase diagnostic accuracy of vulnerable plaques. We have developed an integrated IVUS-OCT imaging apparatus, which includes the integrated catheter, motor drive unit, and imaging system. The dual-function imaging catheter has the same diameter of current clinical standard. The imaging system is capable for simultaneous IVUS and OCT imaging in real time. Ex vivo and in vivo experiments on rabbits with atherosclerosis were conducted to demonstrate the feasibility and superiority of the integrated intravascular imaging modality

Mining Prognostic Significance of MEG3 in Human Breast Cancer Using Bioinformatics Analysis

Background/Aims: Maternally expressed gene 3 (MEG3) is an imprinted gene with maternal expression, which may function as a tumor suppressor by inhibiting angiogenesis. To identify the prognostic value of MEG3 in breast cancer, systematic analysis was performed in this study. Methods: To evaluate gene alteration during breast carcinogenesis, we explored MEG3 expression using the Serial Analysis of Gene Expression Genie suite and Oncomine analysis. The prognostic roles of MEG3 in breast cancer were investigated using the PrognoScan database. The heat map and methylation status of MEG3 were determined using the UCSC Genome Browser. Results: We found that MEG3 was more frequently downregulated in breast cancer than in normal tissues and this correlated with prognosis. However, estrogen receptor and progesterone receptor status were found to be positively correlated with MEG3 expression. Conversely, basal-like status, triple-negative breast cancer status, and Scarff Bloom &#38; Richardson grade criterion were negatively correlated with MEG3 expression. Following data mining in multiple big data databases, we confirmed a positive correlation between MEG3 and heparan sulfate proteoglycan 2 (HSPG2) expression in breast cancer tissues. Conclusion: MEG3 could be adopted as a marker to predict the prognosis of breast cancer with HSPG2. However, large-scale and comprehensive research is needed to clarify our results

Analysis of seismic anisotropy in 3D multi-component seismic data

The importance of seismic anisotropy has been recognized by the oil industry since its first observation in hydrocarbon reservoirs in 1986, and the application of seismic anisotropy to solve geophysical problems has been keenly pursued since then. However, a lot of problems remain, which have limited the applications of the technology. Nowadays, more and more 3D multi-component seismic data with wide-azimuth are becoming available. These have provided more opportunities for the study of seismic anisotropy. My thesis has focused on the study of using seismic anisotropy in 3D multi-component seismic data to characterize subsurface fractures, improve converted wave imaging and detect fluid content in fractured reservoirs, all of which are important for fractured reservoir exploration and monitoring. For the use of seismic anisotropy to characterize subsurface fracture systems, equivalent medium theories have established the link between seismic anisotropy and fracture properties. The numerical modelling in the thesis reveals that the amplitudes and interval travel-time of the radial component of PS converted waves can be used to derive fracture properties through elliptical fitting similar to P-waves. However, sufficient offset coverage is required for either the P- or PS-wave to reveal the features of elliptical variation with azimuth. Compared with numerical modelling, seismic physical modelling provides additional insights into the azimuthal variation of P and PS-wave attributes and their links with fracture properties. Analysis of the seismic physical model data in the thesis shows that the ratio of the offset to the depth of a target layer (offset-depth ratio), is a key parameter controlling the choice of suitable attributes and methods for fracture analysis. Data with a small offset-depth ratio from 0.7 to 1.0 may be more suitable for amplitude analysis; whilst the use of travel time or velocity analysis requires a large offset-depth ratio above 1.0, which can help in reducing the effect of the acquisition footprint and structural imprint on the results. Multi-component seismic data is often heavily contaminated with noise, which will limit its application potential in seismic anisotropy analysis. A new method to reduce noise in 3D multi-component seismic data has been developed and has proved to be very helpful in improving data quality. The method can automatically recognize and eliminate strong noise in 3D converted wave seismic data with little interference to useful reflection signals. Component rotation is normally a routine procedure in 3D multi-component seismic analysis. However, this study shows that incorrect rotations may occur for certain acquisition geometry and can lead to errors in shear-wave splitting analysis. A quality control method has been developed to ensure this procedure is correctly carried out. The presence of seismic anisotropy can affect the quality of seismic imaging, but the study has shown that the magnitude of the effects depends on the data type and target depth. The effects of VTI anisotropy (transverse isotropy with a vertical symmetry axis) on P-wave images are much weaker than those on PS-wave images. Anisotropic effects decrease with depth for the P- and PS-waves. The real data example shows that the overall image quality of PS-waves processed by pre-stack time migration has been improved when VTI anisotropy has been taken into account. The improvements are mainly in the upper part of the section. Monitoring fluid distribution is an important task in producing reservoirs. A synthetic study based on a multi-scale rock-physics model shows that it is possible to use seismic anisotropy to derive viscosity information in a HTI medium (transverse isotropy with a horizontal symmetry axis). The numerical modelling demonstrates the effects of fluid viscosity on medium elastic properties and seismic reflectivity, as well as the possibility of using them to discriminate between oil and water saturation. Analysis of real data reveals that it is hard to use the P-wave to discriminate oil-water saturation. However, characteristic shear-wave splitting behaviour due to pore pressure changes demonstrates the potential for discriminating between oil and water saturation in fractured reservoirs.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A Practical Route for the Preparation of 1,4,7-Triazacyclononanyl Diacetates with a Hydroxypyridinonate Pendant Arm

The preparation of triazamacrocyclic hydroxypyridinonate (HOPO-TACN) derivatives as potential chelators for metals in biomedical applications was reported. The synthesis is based on a convergent synthetic approach, in which the key intermediate di-tert-butyl-2,2′-(1,4,7-triazonane-1,4-diyl) diacetate was coupled with a hydroxypyridinonate pendant arm. The method is suitable for rapid syntheses of metal chelator HOPO-TACNs of biomedical interest

Integrated ultrasound and photoacoustic probe for co-registered intravascular imaging.

We report on the synergy of an integrated ultrasound (US) and photoacoustic (PA) probe system for intravascular imaging. The combined dual-modality probe is based on a 39 MHz ring-shaped US transducer which detects both US echoes and laser-generated PA signals. By combining optical fiber, US transducer, and micromirror, we can obtain intravascular cross-sectional B-scan images by internal illumination of the sample. The performance of the probe is evaluated in a phantom study. Moreover, the coaxially designed probe also provides co-registered US and PA images of a normal rabbit aorta, which demonstrates the imaging ability of the dual-functional system, implying future clinical applications

Intravascular photoacoustic imaging at 35 and 80 MHz

Abstract.The catheter-based intravascular photoacoustic (IVPA) imaging for diagnosing atherosclerosis, which can provide optical absorption contrast of the arterial wall besides acoustic scattering contrast from the conventional intravascular ultrasound (IVUS) imaging, has been intensively researched recently. The resolution of IVPA is determined by the frequency bandwidth of an ultrasonic transducer. Higher resolution can be achieved by increasing the transducer’s working frequency and bandwidth. We introduce IVPA imaging at 35 and 80 MHz by using newly designed integrated IVUS/IVPA probes. This is the first time IVPA has been achieved as high as 80 MHz. Six-micrometer tungsten wires were imaged to evaluate the probes’ spatial resolutions and beam patterns. Healthy rabbit aorta was imaged in vitro. Imaging results show that IVPA has superior contrast over IVUS in identifying the arterial wall, and IVPA at 80 MHz demonstrates extraordinary resolution (35 μm) compared to 35 MHz

Integrated ultrasound and photoacoustic probe for co-registered intravascular imaging.

We report on the synergy of an integrated ultrasound (US) and photoacoustic (PA) probe system for intravascular imaging. The combined dual-modality probe is based on a 39 MHz ring-shaped US transducer which detects both US echoes and laser-generated PA signals. By combining optical fiber, US transducer, and micromirror, we can obtain intravascular cross-sectional B-scan images by internal illumination of the sample. The performance of the probe is evaluated in a phantom study. Moreover, the coaxially designed probe also provides co-registered US and PA images of a normal rabbit aorta, which demonstrates the imaging ability of the dual-functional system, implying future clinical applications