Study on a novel omnidirectional ultrasonic cavitation removal system for Microcystis aeruginosa.

Microcystis aeruginosa, as a typical alga, produces microcystin with strong liver toxicity, seriously endangering the liver health of human and animals. Inhibiting the bloom of the Microcystis aeruginosa in lakes becomes a significant and meaningful work. Ultrasonic cavitation is currently considered to be the most environmentally friendly and effective method for the removal of Microcystis aeruginosa. However, the commercialized ultrasonic algae removal systems require multi-Langevin transducers to achieve omnidirectional ultrasonic irradiation due to the single irradiation direction of the Langevin transducer, resulting in the complex design and high energy consumption. To achieve a low-cost, simple structure, and high-efficiency algae removal system, a novel omnidirectional ultrasonic cavitation removal system for Microcystis aeruginosa is proposed. The proposed system is major composed of a novel omnidirectional ultrasonic transducer, which generates the omnidirectional ultrasonic irradiation by its shaking-head motion coupled by two orthogonal bending vibration modes. Modal simulation, sound field simulation, and cavitation bubble radius simulation are first carried out to optimize the geometric sizes of the proposed transducer and verify the correctness of the omnidirectional ultrasonic irradiation principle. Then the vibration characteristics of the transducer prototype are measured by vibration tests and impedance tests. Finally, the feasibility and effectiveness of the proposed omnidirectional ultrasonic removal system for Microcystis aeruginosa are evaluated through the algae removal experiments. The experimental results exhibit that the algal cells damaged by ultrasonic irradiation from the proposed system do not have the ability to self-repair. In addition, the algal removal rates reached 55.41% and 72.97% after 30 min of ultrasonic treatment when the corresponding ultrasonic densities are 0.014 W/mL and 0.021 W/mL, respectively. The proposed omnidirectional ultrasonic algae removal system significantly simplifies the configuration and reduces energy consumption, presenting the potential promise of algae removal and environmental protection.

Role of Contrast-Enhanced Ultrasound in Diagnosis of Thyroid Nodules in Acoustic Radiation Force Impulse "Gray Zone".

The aim of this study was to evaluate the clinical value of contrast-enhanced ultrasound (CEUS) in the diagnosis of thyroid nodules in the acoustic radiation force impulse (ARFI) "gray zone" (the shear wave velocity is in the range 2.5-3 m/s). ARFI was performed before thyroidectomy in 70 patients with 200 thyroid nodules, and then CEUS was performed in 40 thyroid nodules in the "gray zone." The accuracy of ARFI for the 200 thyroid nodules was 82% (164/200). The accuracy of ARFI for the 40 "gray zone" thyroid nodules was 70% (28/40), whereas the accuracy of CEUS for the "gray zone" thyroid nodules was 90% (36/40). There was a significant difference in accuracy (p < 0.05). CEUS has better accuracy for thyroid nodules in the ARFI "gray zone." CEUS supplemented ARFI in differential diagnosis of benign and malignant thyroid nodules.

Superb Microvascular Imaging-A new vascular detecting ultrasonographic technique for avascular breast masses: A preliminary study.

OBJECTIVES: Superb Microvascular Imaging (SMI) is a new vascular imaging technique detecting a slower velocity that color Doppler flow image (CDFI) cannot. The aim of this study is to evaluate the clinical value of SMI for detecting penetrating vessels (PVs) in avascular breast lesions. METHODS: Seventy-nine patients with 82 breast lesions were examined by conventional ultrasound and diagnosed as Breast Imaging Reporting and Data System (BI-RADS) level 3 or 4. CDFI detected no PVs; subsequently, Power Doppler (PD), Advanced Dynamic Flow (ADF), and SMI were performed to detect any PVs in the breast lesions. RESULTS: Compared with PD or ADF, SMI revealed significantly (P<0.01) higher median numbers of PVs in breast lesions. The area under the receiver operating characteristic curve was 0.914 before the corrected classification versus 0.947 after the corrected classification (P<0.05). CONCLUSIONS: SMI was helpful in the differential diagnosis of benign versus malignant in avascular breast lesions, especially those in BI-RADS category 4.

Acoustic radiation force impulse imaging (ARFI) for differentiation of benign and malignant thyroid nodules--A meta-analysis.

OBJECTIVES: Work-up of thyroid nodules remains challenging. Acoustic radiation force impulse imaging (ARFI)-generated shear wave elastography, which can measure quantitatively tissue stiffness (virtual touch tissue quantification) is used as a complement to conventional sonography for improving the diagnosis of thyroid nodules. This meta-analysis was performed to expand on a previous meta-analysis to assess the diagnostic power of ARFI in differentiating benign and malignant thyroid nodules. METHODS: The MEDLINE, PubMed, SpringerLink databases up to December 31, 2014, were searched. The pooled sensitivity, specificity, and summary receiver operating characteristic curve were obtained from individual studies with a random effects model. RESULTS: Sixteen studies that included a total of 2436 nodules in 2147 patients for ARFI studies were analyzed. The overall mean sensitivity and specificity of ARFI for differentiation of thyroid nodules were 0.80 (95% confidence interval [CI], 0.73-0.87) and 0.85 (95% CI, 0.80-0.90), respectively. A significant heterogeneity was found for both sensitivity and specificity of the different studies (P<0.001). The area under the curve for the ARFI was 0.91. CONCLUSIONS: ARFI has high sensitivity and specificity for identification of thyroid. This technique might be useful to select patients with thyroid nodules for surgery.

Expression level of miR-155 in peripheral blood.

OBJECTIVE: To investigate the relationship between the expression level of miR-155 and the severity of coronary lesion, and explore the action mechanism. METHODS: Peripheral blood mononuclear cells (PBMC) were isolated form blood simple from patients with acute myocardial infarction (AMI), unstable angina (UAP), stable angina (SAP) and chest pain syndrome (CPS). RT-PCR was performed to analysis the expression level of miR-155 in peripheral blood mononuclear cells, plasma and RAW264.7 macrophagocyte. MTT was used to analyze the cell viability of OxLDL treated RAW264.7 macrophagocyte. RESULTS: The expression level of miR-155 in blood sample from coronary heart disease patients was much lower than in the blood sample of non-coronary heart disease (P<0.05). The level of miR-155 in PBMCs was much higher in the blood sample from CPS group than the other three group, and the level of miR-155 in plasma was higher in the CPS group than in the UAP and the AMI group, the difference was statistically significant (P<0.05). The expression level of miR-155 in PBMCs is positively associated with the level in the plasma (r=0.861, P=0.000). OxLDL can induce the expression of miR-155 in RAW264.7 macrophagocyte, decrease the cell viability of RAW264.7 macrophagocyte, and with the concentration and the treatment time of OxLDL increased, the effort become more obvious. The inhibition effort of OxLDL to RAW264.7 macrophagocyte with high miR-155 expression is much lower than the control group, and it is statistically significant after treated for 12, 24 and 48 h. CONCLUSIONS: miR-155 plays a protective role in the progression of atherosclerosis, and it may be achieved by reducing the apoptosis effort of OxLDL to RAW264.7 macrophagocyte.

The origin of high activity but low CO(2) selectivity on binary PtSn in the direct ethanol fuel cell.

The most active binary PtSn catalyst for direct ethanol fuel cell applications has been studied at 20 °C and 60 °C, using variable temperature electrochemical in situ FTIR. In comparison with Pt, binary PtSn inhibits ethanol dissociation to CO(a), but promotes partial oxidation to acetaldehyde and acetic acid. Increasing the temperature from 20 °C to 60 °C facilitates both ethanol dissociation to CO(a) and then further oxidation to CO2, leading to an increased selectivity towards CO2; however, acetaldehyde and acetic acid are still the main products. Potential-dependent phase diagrams for surface oxidants of OH(a) formation on Pt(111), Pt(211) and Sn modified Pt(111) and Pt(211) surfaces have been determined using density functional theory (DFT) calculations. It is shown that Sn promotes the formation of OH(a) with a lower onset potential on the Pt(111) surface, whereas an increase in the onset potential is found upon modification of the (211) surface. In addition, Sn inhibits the Pt(211) step edge with respect to ethanol C-C bond breaking compared with that found on the pure Pt, which reduces the formation of CO(a). Sn was also found to facilitate ethanol dehydrogenation and partial oxidation to acetaldehyde and acetic acid which, combined with the more facile OH(a) formation on the Pt(111) surface, gives us a clear understanding of the experimentally determined results. This combined electrochemical in situ FTIR and DFT study provides, for the first time, an insight into the long-term puzzling features of the high activity but low CO2 production found on binary PtSn ethanol fuel cell catalysts.

Assessment of left ventricular diastolic dysfunction based on the intraventricular velocity difference by vector flow mapping.

OBJECTIVES: The diastolic intraventricular velocity difference represents diastolic function of the left ventricle (LV). Here we analyzed the LV diastolic intraventricular velocity difference in patients with impaired LV function based on the ventricular flow rate profile by vector flow mapping. METHODS: Patients with LV diastolic dysfunction were divided into 2 groups: chronic heart failure with restricted filling (group 1; n = 27) and hypertension with abnormal relaxation (group 2; n = 34). Healthy participants were identified as controls (group 3; n = 22). Left ventricular inflow color Doppler findings were analyzed by the vector profile model with the vector flow mapping technology offline. The flow velocity rates at the base and apex of the LV were measured from vector profiles with the vector flow mapping technology. The diastolic intraventricular velocity difference was calculated from flow velocity rates. RESULTS: The diastolic intraventricular velocity difference calculated from vector flow mapping was significantly lower in both groups with LV diastolic dysfunction than the control group (mean ± SD, 79.95 ± 9.88 cm/s in controls versus 40.35 ± 6.80 cm/s in group 1 and 48.50 ± 6.03 cm/s in group 2; P < .001 for both). The diastolic intraventricular velocity difference had a significant association with the ejection fraction (P = .0002) and deceleration time (P = .0306). The peak atrial contraction velocity was negatively related to the diastolic intraventricular velocity difference (P = .0003). CONCLUSIONS: The diastolic intraventricular velocity difference derived from the LV velocity rate by the vector profile model on vector flow mapping can be potentially used for quantitative assessment of LV diastolic function. Vector flow mapping proved to be clinically practical for reflecting LV diastolic dysfunction in pathologic states.

WC@meso-Pt core-shell nanostructures for fuel cells.

We developed a facile method to synthesize core-shell WC@meso-Pt nanocatalysts by carburizing ammonium tungstate and copper nitrate via gas-solid reactions, followed by a Pt replacement reaction. The mesoporous nanocomposite displays higher activity and stability towards methanol electrooxidation than commercial Pt/C catalysts.

Spatial distribution of wall shear stress in common carotid artery by color Doppler flow imaging.

The purpose of this study is to provide a novel approach for measuring the spatial distribution of wall shear stress (WSS) in common carotid artery in vivo. WSS distributions were determined by digital image processing from color Doppler flow imaging (CDFI) in 50 healthy volunteers. In order to evaluate the feasibility of the spatial distribution, the mean values of WSS distribution were compared to the results of conventional WSS calculating method (Hagen-Poiseuille formula). In our study, the mean value of WSS distribution from 50 healthy volunteers was (6.91 ± 1.20) dyne/cm(2), while it was (7.13 ± 1.24) dyne/cm(2) by Hagen-Poiseuille approach. The difference was not statistically significant (t = -0.864, p = 0.604). Hence, the feasibility of the spatial distribution of WSS was proved. Moreover, this novel approach could provide three-dimensional distribution of shear stress and fusion image of shear stress with ultrasonic image for each volunteer, which made WSS "visible". In conclusion, the spatial distribution of WSS could be used for WSS calculation in vivo. Moreover, it could provide more detailed values of WSS distribution than those of Hagen-Poiseuille formula.