The Aortic Annulus Stabilization Technique Prevents Paravalvular Leaks after Rapid Deployment Aortic Valve Implantation

Background: Surgical aortic valve replacement with rapid deployment bioprosthesis guarantees good hemodynamic results but carries the risk of paravalvular leaks. To address this issue, an annulus stabilization technique has been recently developed. Methods: Clinical and hemodynamic parameters from patients treated for aortic valve replacement with the rapid deployment bioprosthesis and a concomitant annulus stabilization technique were prospectively collected and retrospectively analyzed. Echocardiographic data at discharge and at 1-year follow-up were collected and analysed. Results: A total of 57 patients (mean age 74.3 ± 6.1 years) with symptomatic aortic valve stenosis underwent aortic valve replacement with the rapid deployment bioprosthesis and concomitant annulus stabilization technique (mean valve size: 23.8 ± 1.9 mm). Combined procedures accounted for 56.1%. Hospital mortality was 1.8% and a new pacemaker for conduction abnormalities was implanted in 10 patients. The pre-discharge echocardiographic control showed absence of paravalvular leaks of any degree in all patients with mean valve gradient of 9.6 ± 4.0 mmHg. The 1-year echocardiographic control confirmed the good valve hemodynamic (mean gradient of 8.0 ± 2.8 mmHg) and absence of leaks. Conclusion: In this preliminary clinical experience, the annulus stabilization technique prevents postoperative paravalvular leaks after rapid deployment aortic valve implantation, up to 1-year postoperatively. Studies on larger series are of paramount importance to confirm the long-term efficacy of this new surgical technique.

Hydro-Mechanics Analysis on the Strength Development of Cement-Stabilized Sand

Deep cement mixing is an effective ground stabilization technique to control the ground movement on sand areas, and most of the projects have the problem of seepage. The cement slurry is in a fluid state before the initial setting time, the seepage may affect the diffusion process of cement slurry during this period. A hydro-mechanical approach is proposed to investigate the interaction between the seepage and the strength of cement-stabilized sand. The diffusion of the cement slurry under seepage is considered in this study and the diffusion process is simulated by the finite element method. According to the cement concentration at the end of the diffusion process, the strength of cement-stabilized sand can be predicted by combining an empirical formula. Simulation results examine that the existence of seepage and cracks can enhance the non-uniform diffusion process of cement slurry, and the actual strength distribution of the deep cement-mixed sand is far from the ideal state. This indicates that the influence of seepage on the strength of cement-stabilized sand should be considered in the design of projects.

EFFECT OF ROOT OF VETIVER GRASS AND THE SHEAR STRENGTH OF ROOT IN PERMEATED SOIL

Recently, bioengineering has been approached as one of the slope stabilizations techniques as it is inexpensive compared to the mechanical stabilization technique. However, numbers of slope failure still reoccur due to the limitation of the bioengineering technique knowledge. Proper bioengineering material and methods must be carefully selected to overcome the problem. The objectives of this research are to determine the physical and mechanical properties of soil with Vetiver Grass roots as well as the root properties of the Vetiver Grass since these grass types have been applied widely for slope stabilization. The physical properties of soil lab tests have been determined such as compaction test, Atterberg limits test and sieve analysis test. The mechanical properties of soil with and without root grasses have been carried out through the shear box test. For the identification of the root properties of Vetiver Grass, the root morphology and the diameter of the root has been identified. The results for the lab tests conducted showed that the soil with roots have a higher shear strength compared to soil without roots included with FOS (Factor of Safety) calculation proving that the soil with the aid of Vetiver Grass will be effective in retaining soil.

Layer-by-Layer-Stabilized Plasmonic Gold-Silver Nanoparticles on TiO2: Towards Stable Solar Active Photocatalysts

To broaden the activity window of TiO2, a broadband plasmonic photocatalyst has been designed and optimized. This plasmonic ‘rainbow’ photocatalyst consists of TiO2 modified with gold–silver composite nanoparticles of various sizes and compositions, thus inducing a broadband interaction with polychromatic solar light. However, these nanoparticles are inherently unstable, especially due to the use of silver. Hence, in this study the application of the layer-by-layer technique is introduced to create a protective polymer shell around the metal cores with a very high degree of control. Various TiO2 species (pure anatase, PC500, and P25) were loaded with different plasmonic metal loadings (0–2 wt %) in order to identify the most solar active composite materials. The prepared plasmonic photocatalysts were tested towards stearic acid degradation under simulated sunlight. From all materials tested, P25 + 2 wt % of plasmonic ‘rainbow’ nanoparticles proved to be the most promising (56% more efficient compared to pristine P25) and was also identified as the most cost-effective. Further, 2 wt % of layer-by-layer-stabilized ‘rainbow’ nanoparticles were loaded on P25. These layer-by-layer-stabilized metals showed superior stability under a heated oxidative atmosphere, as well as in a salt solution. Finally, the activity of the composite was almost completely retained after 1 month of aging, while the nonstabilized equivalent lost 34% of its initial activity. This work shows for the first time the synergetic application of a plasmonic ‘rainbow’ concept and the layer-by-layer stabilization technique, resulting in a promising solar active, and long-term stable photocatalyst.

Recent Development and Future Perspectives of Quality Control and Assurance for the Deep Mixing Method

The deep mixing method (DMM), an in situ soil stabilization technique, was developed in Japan and Nordic countries in the 1970s and has gained increased popularity in many countries. The quality of stabilized soil depends upon many factors, including its type and condition, the type and amount of binder, and the production process. Quality control and quality assurance (QC/QA) practices focus on stabilized soil, and comprises laboratory mix tests, field trial tests, monitoring and controlling construction parameters, and verification. QC/QA is one of the major concerns for clients and engineers who have less experience with the relevant technologies. In this manuscript, the importance of QC/QA-related activities along the workflow of deep mixing projects is emphasized based on the Japanese experience/results with mechanical mixing technology by vertical shaft mixing tools with horizontal rotating circular mixing blade. The current and recent developments of QC/QA are also presented.

Locking Multi-Laser Frequencies to a Precision Wavelength Meter: Application to Cold Atoms

We herein report a simultaneous frequency stabilization of two 780-nm external cavity diode lasers using a precision wavelength meter (WLM). The laser lock performance is characterized by the Allan deviation measurement in which we find σy=10−12 at an averaging time of 1000 s. We also obtain spectral profiles through a heterodyne spectroscopy, identifying the contribution of white and flicker noises to the laser linewidth. The frequency drift of the WLM is measured to be about 2.0(4) MHz over 36 h. Utilizing the two lasers as a cooling and repumping field, we demonstrate a magneto-optical trap of 87Rb atoms near a high-finesse optical cavity. Our laser stabilization technique operates at broad wavelength range without a radio frequency element.

A Low Noise High Input Impedance Chopper-Stabilized Biopotential Amplifier with Ripple Reduction Technique

Biopotential signals are created as a result of the electrochemical activity of the many cells that comprise the nervous system, and they represent both normal and pathological organ function. These signals must be identified with extreme caution because they are surrounded by a great deal of noise when detected by sensors. This article explores a novel biopotential amplifier that incorporates the chopper stabilization technique to increase noise performance and minimize offset. However, by introducing the chopper modulator into the proposed design, the amplifier's overall input impedance was lowered, which was then increased to greater than 200 MΩ by adding the forward auxiliary path to the input branch. Additionally, the output ripple, produced due to switching activity and up-sampling, was reduced by inclusion of the R-C ripple removing block at the output of the operational transconductance amplifier (OTA). The designed architecture had a mid-band gain of 40dB with a power consumption of 9 µW and an offset of 10µV and a CMRR of 82 dB. It generated a noise of 42nV/√Hz. Also, the obtained results were compared with a conventional amplifier. The proposed design was verified by carrying out simulations using 180nm technology parameters. Cadence Virtuoso (Schematic editor), Spectre (Simulator), Symica and Magic (Layout) tools were used to complete the implementation and simulation of the proposed design. HIGHLIGHTS Biopotential signals are created as a result of the electrochemical activity of the many cells which must be identified with extreme caution because they are surrounded by a great deal of noise when detected by sensors It explores a novel biopotential amplifier that incorporates the chopper stabilization technique to increase noise performance and minimize offset By introducing the chopper modulator into the proposed design, the amplifier's overall input impedance was lowered, which was then increased to greater than 200 MΩ by adding the forward auxiliary path to the input branch The output ripple, produced due to switching activity and up-sampling, was reduced by inclusion of the R-C ripple removing block at the output of the operational transconductance amplifier (OTA) The designed architecture had a mid-band gain of 40dB with a power consumption of 9 µW and an offset of 10 µV and a CMRR of 82 dB. It generated a noise of 42 nV/√Hz GRAPHICAL ABSTRACT

Mechanical testing of paraosseous clamp-cerclage stabilization compared to interfragmentary wiring and combination technique in L-shape acrylic plate simulate to canine mandibular fracture

The purpose of this research was to comparison of the mechanical strength of the three different stabilization techniques in canine mandibular models. An L-shaped acrylic plate to replicate the mandible of a middle-sized dog was used as a canine mandibular fracture model. The research compared the strength of 3 fixation techniques: interfragmentary wiring, paraosseous clamp-cerclage stabilization, and a combination of both techniques. Each method was tested using 6 acrylic samples and measuring the maximum pressure load on the rostral mandible model using a Hounsfield H50KS testing machine. Statistical analysis was used to summarize the maximum load results from each method. The strengths of the interfragmentary wiring technique and the combination technique were not significantly different, while the paraosseous clamp-cerclage stabilization technique had significantly less strength than the other two techniques. The acrylic samples simulated the mandibular bone in a medium-sized breed dog because there are variable sizes and conformations of the mandible. This method was used to help neutralize other confounding factors associated with using real bone. In conclusion, the combination technique of interfragmentary wiring and paraosseous clamp-cerclage was the best method that can be used for increased stabilization of mandibular fixation. This technique was useful for facilitating stabilization of a mandible at a lower cost compared with the bone plate and screw method.

The Stabilization of Waste Funnel Glass of CRT by SiO2 Film Coating Technique

The funnel glass of the CRT monitor contains about 22–28% of lead oxide, of which lead is a highly toxic species and hazardous to the environment. This study proposes a process to form a protective layer of SiO2 film coating on the funnel glass to reduce the hazardous effect of lead leaching to the environment. The film coating benefits from the advantages of the sol–gel method. There are two key procedures of the stabilization technique, including the alkaline treatment and the formation of SiO2 coating from TEOS. The results show that the funnel glass powder treated with 10 M NaOH can produce a mushy layer on the surface. The mushy layer, which comprises OH− and water, can promote the formation of the SiO2 film layer on the surface of funnel glass powder. The conditions of the SiO2 film coating proposed in this study are: alkaline treatment by 10 M NaOH, the addition ratio of TEOS and funnel glass powder 2: 1, reaction temperature 40 °C, and reaction time 1.3 h. The EDS and ESCA results show that the Pb peak intensity on the surface of funnel glass decreases with the film coating. In the TCLP test, the leaching amount for Pb of the SiO2 film coated funnel glass powders is 0.7 mg/L, which is far lower than the standard in Taiwan EPA. Based on the experimental results, the formation mechanism of the SiO2 film layer on the surface of waste funnel glass powder is proposed. This study demonstrates that the SiO2 film coating is a potentially effective method to solve the problem of the waste funnel glass.