Duty Cycle Time Research Articles

Optimized Ultrasound Conditions for Enhanced Sensitivity of Molecular Beacons in the Detection of MDR1 mRNA in Living Cells

P-glycoprotein (P-gp), aprognostic indicator for chemotherapy failure, is encoded by multidrug resistance gene (MDR1). MDR1 mRNA expression could serve as a guidance for personalized medicine. However, the traditional PCR process for mRNA measurement is complicated and cannot realize the real-time detection of mRNA in living single cells. In this work, optimized gold nanoparticle-based molecular beacons were employed to determine MDR1 mRNA levels in living cancer cells. To improve detection sensitivity, ultrasound (US) irradiation was applied to facilitate and enhance cellular uptake of hairpin DNA-coated gold nanoparticle (hDAuNP). The US conditions including irradiation power, exposure time, duty cycle, and incubation time were optimized. The slight difference in MDR1 expression manipulated by siRNA silence could be recognized by US assisted hDAuNP beacons; a 10-fold increase of detection sensitivity was achieved compared with the nonultrasound assistance. Meanwhile, the detection cycle could be shortened from 12 to 2 h. Furthermore, this hDAuNP beacon can serve as an antisense agent to down-regulate P-gp expression and to reverse drug resistance of MCF-7/Adr cells to doxorubicin. Our results demonstrated that the MDR1 hDAuNP beacon assisted by US irradiation had great potential to predict chemotherapy sensitivity and to overcome multidrug resistance in cancer cells and was thus a promising tool for individualized medicine.

Purification of serratiopeptidase from Serratia marcescens NRRL B 23112 using ultrasound assisted three phase partitioning

The ultrasound assisted three phase partitioning (UATPP) is a novel bioseparation method for separation and purification of biomolecules. In the present work, UATPP was investigated for the first time for purification of serratiopeptidase from Serratia marcescens NRRL B 23112. Effect of various process parameters such as ammonium sulphate saturation, t-butanol to crude extract ratio, pH, ultrasonic frequency, ultrasonic intensity, duty cycle and irradiation time were evaluated and optimized. The optimized conditions were found to be as follows: ammonium sulphate saturation 30% (w/v), pH 7.0, t-butanol to crude ratio 1:1 (v/v), ultrasound frequency 25kHz, ultrasound intensity 0.05W/cm2, duty cycle 20% and irradiation time 5min. The maximum purity and recovery obtained from UATPP was 9.4-fold and 96% respectively as compared to the three phase partitioning (TPP) (4.2-fold and 83%). Also the process time for UATPP was significantly reduced to 5min from 1h as compared to TPP. The results indicate that, UATPP is an efficient technique for the purification of serratiopeptidase with maximum purity, recovery and reduced processing time.

PulSED: pulsed sonoelectrodeposition of fractal nanoplatinum for enhancing amperometric biosensor performance.

For the first time, we combine pulsed electrodeposition with out-of-phase pulsed sonication for controlled synthesis of fractal nanoplatinum structures as the transducer layer in electrochemical sensing. We develop and test this technique, called bimodal pulsed sonoelectrodeposition (pulSED), as a simple approach for creating highly conductive transducer nanometals for use in sensing and biosensing. We first compared the efficiency of pulSED nanoplatinum to other pulsed electrodeposition techniques, and then explored the effect of duty cycle and plating time on electroactive surface area and nanoparticle size/morphology. The developed pulSED nanoplatinum displayed fractal features with a relatively homogenous size distribution (26.31 ± 1.3 nm) and extremely high electroactive surface (0.28 ± 0.04 cm(2)) relative to other electroplating techniques (up to one order of magnitude higher). A high duty cycle (900 mHz) promotes formation of stable nanostructures (including fractal nanostructures) and reduces amorphous structure formation due to bubble cavitation and enhanced mass transport of metal ions to the electrode surface. To demonstrate the applicability of the pulSED technique, non-enzymatic and enzymatic sensors were developed for measuring hydrogen peroxide and glucose. The sensitivity for non-enzymatic peroxide sensing (3335 ± 305 μA cm(-2) mM(-1)), non-enzymatic glucose sensing (73 ± 14 μA cm(-2) mM(-1)) and enzymatic glucose biosensing (155 ± 25 μA cm(-2) mM(-1)) was higher than, or similar to, other nanomaterial-mediated amperometric sensors reported in the literature. The pulSED technique is a one pot method for tunable synthesis of nanometal structures as a transducer layer in electrochemical sensing and biosensing that requires no precursors or capping agents, and can be carried out at room temperature with inexpensive hardware.

Surface modification of polyacrylonitrile co-polymer membranes using pulsed direct current nitrogen plasma

Low temperature plasma treatment using pulsed direct current discharge of nitrogen gas was employed to enhance hydrophilicity of the polyacrylonitrile co-polymer membranes. The membranes were characterized in terms of morphology, structure, hydrophilicity, and membrane performance. Properties and functional groups on the surface of polyacrylonitrile co-polymer membranes were investigated by contact angle, scanning electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. Effects of plasma conditions, namely, pulsed voltage, duty cycle and treatment time on increase in membrane hydrophilicity were studied. Permeability of treated membrane was increased by 47% and it was retained up to 70days. Surface etching due to plasma treatment was confirmed by weight loss of the treated membranes. Due to surface etching, average pore size increased and rejection of 200kDa polyethylene glycol decreased to about 70% for the treated membrane. Oxygen and nitrogen functional groups were responsible for surface hydrophilicity.

Conceptual Design of a Helium-Cooled Ceramic Breeder Blanket for CFETR

The China Fusion Engineering Test Reactor (CFETR) is a superconducting tokamak reactor proposed by the China National Integration Design Group. The aim is to develop China’s next-step fusion device. A helium-cooled ceramic breeder (HCCB) blanket concept has been put forward by the blanket integration design team of the Institute of Plasma Physics of the Chinese Academy of Sciences. The present blanket configuration is based on the upper port dimension and maintenance scheme. The HCCB blanket comprises a U-shaped first wall, cap, breeder unit, middle plate, and back plate. The breeder unit includes a cooling plate, beryllium pebble bed, and lithium silicate pebble bed. The structure of the HCCB blanket concept is obviously different from the ITER HCCB test blanket module of China. The CFETR HCCB blanket will meet the requirements of CFETR long-pulse or steady-state operation with a duty cycle time greater than 0.3. The maintenance scheme of the blanket is introduced in this paper. Three-dimensional neutronic analysis results show that the tritium breeding ratio can satisfy the design requirement. Besides, the thermal-hydraulic behavior of the first wall has been studied using ANSYS CFX code.

Optimization of low-frequency low-intensity ultrasound-mediated microvessel disruption on prostate cancer xenografts in nude mice using an orthogonal experimental design.

The present study aimed to provide a complete exploration of the effect of sound intensity, frequency, duty cycle, microbubble volume and irradiation time on low-frequency low-intensity ultrasound (US)-mediated microvessel disruption, and to identify an optimal combination of the five factors that maximize the blockage effect. An orthogonal experimental design approach was used. Enhanced US imaging and acoustic quantification were performed to assess tumor blood perfusion. In the confirmatory test, in addition to acoustic quantification, the specimens of the tumor were stained with hematoxylin and eosin and observed using light microscopy. The results revealed that sound intensity, frequency, duty cycle, microbubble volume and irradiation time had a significant effect on the average peak intensity (API). The extent of the impact of the variables on the API was in the following order: Sound intensity; frequency; duty cycle; microbubble volume; and irradiation time. The optimum conditions were found to be as follows: Sound intensity, 1.00 W/cm2; frequency, 20 Hz; duty cycle, 40%; microbubble volume, 0.20 ml; and irradiation time, 3 min. In the confirmatory test, the API was 19.97±2.66 immediately subsequent to treatment, and histological examination revealed signs of tumor blood vessel injury in the optimum parameter combination group. In conclusion, the Taguchi L18 (3)6 orthogonal array design was successfully applied for determining the optimal parameter combination of API following treatment. Under the optimum orthogonal design condition, a minimum API of 19.97±2.66 subsequent to low-frequency and low-intensity mediated blood perfusion blockage was obtained.

Electromagnetic Parameters Analysis of CFETR Magnets

CFETR (China Fusion Engineering Test Reactor) is a test reactor which shall be constructed by National Integration Design Group for Magnetic Confinement Fusion Reactor of China. The reactor has the equivalent scale compared with ITER, but has the complementary function to ITER. CFETR is a demonstration of long pulse or steady state operation with duty cycle time is not less than 0.3–0.5 and the full cycle of tritium self-sustained with TBR is not less than 1.2. The magnets design of CFETR is based on the ITER magnet technology. Electromagnetic parameters analysis is one of the most important tasks for the magnets design in fusion device. These parameters can be used to verify the feasibility of physics and engineering conceptual design. This paper provides the electromagnetic parameters of the CFETR magnet system, and all these parameters meet the physics and engineering requirements which shows that the design of CFETR magnets system is reasonable.

Electrical method to measure the transient thermal impedance of insulated gate bipolar transistor module

The thermal characterisation of insulated gate bipolar transistor (IGBT) module is very important, since the production consistency and reliability are affected when IGBT is exploited in high temperature. To investigate the transient thermal behaviour of IGBT, a transient thermal impedance (Z th) measurement system was built using the electrical method with gate-emitter voltage as temperature-sensitive parameter. Factors affecting the Z th measurement, such as environment temperature, heating power, duty cycle and heating time, were discussed in detail. The Z th of each component within IGBT module was measured by selecting right heating time before thermal equilibrium. It is found that the Z th measurement has high accuracy and repeatability, which is helpful to understand how thermal performance of IGBT module varies with architecture and material properties for power electronic packaging.

Structural design and preliminary analysis of liquid lead–lithium blanket for China Fusion Engineering Test Reactor

China Fusion Engineering Test Reactor (CFETR) has been proposed as an option in China to bridge the gaps between ITER and fusion power plant. Since one major goal of CFETR is to demonstrate long pulse or steady-state operation with duty cycle time ≥0.3–0.5, easier maintenance of the in-vessel components is emphasized in the design process. In this contribution, a kind of liquid lead–lithium tritium breeder blanket concept focus on the remote maintenance has been designed for CFETR. To make the pipes and mechanical connections at the rear of the blanket accessible from vacuum vessel, two kinds of guide tubes were adopted to provide passageways for remote handling tools. In order to evaluate the effects of the guide tube installation on the structural performance of the blanket, as a preliminary stage, thermal-hydraulic analysis of first wall was carried out based on the heat load obtained from 3D modeled neutronics calculations. In addition, thermal stress analysis of the first wall under normal condition was performed to evaluate the thermomechanical behavior. The preliminary analysis results validated the performance of current blanket design.

Fine-Tuning Pulse Reverse Electrodeposition for Enhanced Photoelectrochemical Water Oxidation Performance of α-Fe2O3 Photoanodes

High-quality hematite (α-Fe2O3) photoanodes were synthesized from a sulfate electrolyte bath by the pulse reverse electrodeposition (PRED) method. The influence of PRED parameters (viz. duty cycle, pulse period, and deposition time) was systematically investigated on the structural, optical, morphological, and photoelectrochemical properties of the films. The optimized parameters of pulse duty cycle, pulse period, and the deposition time were 20%, 10 ms, and 45 s, respectively. The granular and compact nanocrystalline morphology of the α-Fe2O3 was found to alter according to the process parameters. The α-Fe2O3 electrodes (film thickness ∼200 nm) prepared by annealing at 550 °C for 4 h followed by 800 °C for 15 min exhibited an optimum photocurrent density of 504 μA cm–2 measured at 1.23 V vs RHE in 1 M NaOH electrolyte under 100 mW cm–2 light illumination.

Engineering conceptual design of CFETR divertor

The China Fusion Engineering Test Reactor (CFETR), which is in conceptual design phase, aims at producing fusion power of 50–200MW with tritium breeding ratio of ∼1.2 and duty cycle time of 0.3–0.5. Its designed main parameters are major/minor radii of 5.7m/1.6m and plasma current of 10MA. Although the fusion power is lower than the one of ITER, the relative smaller machine dimensions and planed much higher auxiliary heating power of 100–140MW make that the power exhausting for the CFETR divertor is a very critical issue. To solve this issue, the divertor should be better designed with advanced physical operation mode, advanced configuration/geometry or high efficient cooling structure. In the paper, much effort was put on the divertor configuration and geometry. With designed magnet system, three divertor configurations can be realized, ITER-like, snowflake and super-X. However, considering structural design feasibility and remote handling compatibility, only the first two configurations were selected for the first step of engineering design. Three divertors were designed. They have different first wall geometries to accommodate with different plasma configurations, one for the ITER-like, one for the snowflake and the third one for both the configurations. All three divertors employ the same cassette body as the support and the cooling water manifold for the first wall. This feature simplifies the interface of the divertor to other components in the vacuum vessel. Besides, the cooling structure and the remote maintenance concept are also introduced in the paper.

Evaluation of target-plate heat flux for a possible snowflake divertor in CFETR using SOLPS

China Fusion Engineering Test Reactor (CFETR) is proposed as a good complement to ITER for demonstration of fusion energy. CFETR is based on both physics and some technologies of ITER. The main goals of CFETR are fusion power Pf=50–200MW, duty cycle time ⩾0.3–0.5, and a tritium breeding ratio ∼1.2. To explore a more effective way to manage heat exhaust in a future fusion reactor, which will have higher heating power (auxiliary heating power plus 20% of the fusion power) than ITER, a snowflake divertor (SFD) is an optional choice considered for CFETR. In this paper, the preliminary design of a SFD for CFETR is presented, including the divertor magnetic configuration and geometry. A numerical simulation is then performed to evaluate the heat flux onto the divertor targets by using SOLPS.

Ultrasound-assisted extraction of antioxidants in Misai Kucing (Orthosiphon stamineus).

Ultrasound-assisted extraction (UAE) with ethanol was used to extract the compounds responsible for the antioxidant activities of Misai Kucing (Orthosiphon stamineus). Response surface methodology (RSM) was used to optimize four independent variables: ethanol concentration (%), amplitude (%), duty cycle (W/s) and extraction time (min). Antioxidant compounds were determined by total phenolic content and total flavonoid content to be 1.4 g gallic acid equivalent/100 g DW and 45 g catechin equivalent/100 g DW, respectively. Antioxidant activities were evaluated using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) radical scavenging capacity assay and the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging capacity assay to be 1,961.3 and 2,423.3 µmol Trolox Equivalent Antioxidant Capacity (TEAC)/100 g DW, respectively. Based on the optimal conditions, experimental values were reported to be close to the predicted value by RSM modeling (p > 0.05), indicating the suitability of UAE for extracting the antioxidants of Misai Kucing. Rosmarinic acid, kaempferol-rutinoside and sinesetine were identified by high performance liquid chromatography-mass spectrometry.

Ionic liquid based ultrasonic-assisted extraction of forskolin from Coleus forskohlii roots

Ionic liquid based ultrasonic-assisted extraction (ILUAE) was successfully applied to extract forskolin (FSK) from Coleus forskohlii roots. Six ionic liquids with different cations and anions were initially investigated in this work from which tetramethyl guanidium lactate (TMGL) was selected for further studies using ultrasound-assisted extraction. Parameters of ultrasound extraction such as ultrasonic power, duty cycle and extraction time were optimized to get maximum extraction of FSK. The maximum extraction yield of 0.508±0.006% (w/w) corresponding to an extraction efficiency of 87.4±1.04% of FSK was obtained under the optimized conditions. ILUAE offered shorter extraction time (4h) as compared to Soxhlet extraction (12h) which indicated it to be a rapid, efficient, simple and green approach for extracting FSK from Coleus forskohlii roots.

Ultrasound enhanced production and antioxidant activity of polysaccharides from mycelial fermentation of Phellinus igniarius

In this study, a novel flat-plate ultrasound technology was developed to stimulate polysaccharides production from Phellinus igniarius mycelial fermentation. Three-factor-three-level Box–Behnken design was used to optimize ultrasonic treatment time, duty cycle time and culture time for a high yield of P. igniarius polysaccharides (PIPS). Optimal conditions were found to be ultrasound treatment time 65min, duty cycle time 25s, and culture time 3.8d that gave a maximum PIPS yield of 1.8002g/L, which increased ∼22.64% compared with the control (without any ultrasound). PIPS mainly contained low-molecular weight (MW) polysaccharides (3.1kDa, 80%) composed of glucose, rhamnose and mannose in a molar ratio of 11.0:14.0:1.0. PIPS with higher carbohydrate and uronic acid contents exhibited strong antioxidant activities in vitro. Laser scanning confocal microscope (LSCM) observations suggested that ultrasound could change the morphology and structure of P. igniarius mycelium, and accelerate the transfer of nutrients and metabolites.

레이저를 이용한 하지정맥류 치료의 정량화 연구

The purpose of the study was to identify the effect of laser parameters on photocoagulation to maximize safety and efficacy during varicose vein treatment. CW and pulsed modes at 1470 nm were initially compared as a function of power on bovine liver tissue. In the pulsed mode, various parameters including repetition rate, duty cycle, and irradiation time were compared to evaluate tissue response during thermal treatment. The results demonstrated that CW and pulsed modes yielded almost similar coagulation development possibly due to shorter irradiation time of 5 sec. Regardless of laser mode, both repetition rate and duty cycle presented constant coagulation rate whereas longer irradiation time facilitated coagulation process.

Preparation of Pulse Electrodeposited Mo-Ni Coating

Mo-Ni coatings were prepared on Ni alloy by pulse electrodeposition method. The effects of current density, electrodeposition temperature, frequency, duty cycle and electrodeposition time on microhardness of Mo-Ni coating were researched, respectively. Microhardness of Mo-Ni coating increases with the increase of current density, electrodeposition temperature, frequency and electro-deposition time in 17.75 A/dm2 ~ 19.25 A/dm2. 21 °C~ 25 °C, 1000 Hz ~ 5000 Hz and 10 min ~ 20 min, respectively. Microhardness of Mo-Ni coating decreases with the increase of electrodeposition temperature, electrodeposition time and duty cycle in 25 °C ~ 37 °C, 20 min ~ 30 min and 0.5 ~ 0.9, respectively. In the range of current density from 19.25A/dm2 to 20.75 A/dm2, microhardness of Mo-Ni coating is neariy constant with the increase of current density. When electrodeposition parameters: current density 19.25 A/dm2, electro-deposition temperature 25 °C, frequency 5000 Hz, duty cycle 0.5 and electrodeposition time 20 min, microhardness of Mo-Ni coatin is as high as 707.9 HV.

Concept design on RH maintenance of CFETR Tokamak reactor

CFETR which stands for Chinese Fusion Engineering Testing Reactor is a superconducting Tokamak device. The concept design on RH maintenance of CFETR has been done in the past year. It is known that, the RH maintenance is one of the most important parts for Tokamak reactor. The fusion power was designed as 50–200MW and its duty cycle time (or burning time) was estimated as 30–50%. The center magnetic field strength on the TF magnet is 5.0T, the maximum capacity of the volt seconds provided by center solenoid winding will be about 160VS. The plasma current will be 10MA and its major radius and minor radius is 5.7m and 1.6m respectively. All the components of CFETR which provide their basic functions must be maintained and inspected during the reactor lifetime. Thus, the remote handling (RH) maintenance system should be a key component, which must be detailedly designed during the concept design processing of CFETR, for the operation of reactor. The main design work for RH maintenance in this paper was carried out including the divertor RH system, the blanket RH system and the transfer cask system. What is more, the technical problems encountered in the design process will also be discussed.

RAMI Analysis Program Design and Research for CFETR (Chinese Fusion Engineering Testing Reactor) Tokamak Machine

Chinese Fusion Engineering Testing Reactor (CFETR) is a test reactor which shall be constructed by National Integration Design Group for Magnetic Confinement Fusion Reactor of China with an ambitious scientific and technological goal. The reactor has the equivalent scale compared with ITER, but has the complementary function to ITER. CFETR is a demonstration of long pulse or steady-state operation with duty cycle time not less than 0.3–0.5 and the full cycle of tritium self-sustained with TBR not less than 1.2. At the same time it will be exploring options for DEMO blanket and divertor with an easy changeable core by remote handling way. To be able to reach its scientific and technological objectives, as one of technical risks control methods, RAMI analysis need to be done during the hold lifetime of CFETR, from conception design to decommissioning. Base on stating of CFETR lifetime and preliminary operational programme, the RAMI analysis program and process are designed and discussed, it consists of five major steps: (1) functional analysis are performed, (2) calculating reliability block diagrams, (3) analyzing failure mode, effects and criticality analysis, (4) risk mitigation actions are taken to ensure every system is compatibility with RAMI objectives, (5) All the RAMI analysis are integrated as the final RAMI analysis reports to be reviewed in the system final design review. Along with the elements of the analysis the vacuum vessel (VV) system was performed to provide as examples, detailed showing how the CFETR RAMI analysis is carried out. CFETR RAMI analysis guidelines were designed and established, after constantly revised and improved these analysis criteria and programs will become the basis standards for CFETR RAMI analysis. Preliminary RAMI analysis of CFETR VV system was obtained, which will be updated with the VV system design progresses.

Self-selected duty cycle times for grip force, wrist flexion postures and three grip types

Performance and health issues are common in industry. On-the-job productivity gains related to good design, which could help justify ergonomics intervention, are often not considered. More quantitative data are needed to model the discomfort/productivity relationship for upper limb activity in simulated repetitive assembly type work. Eighteen participants completed an experiment, simulating a repetitive upper limb task with force, posture and grip type recorded as independent variables. Duty cycle time and discomfort were recorded as dependent variables. Participants performed 18 experiment combinations (block designed around force); each treatment lasted 35 min, including breaks. Analysis indicated a significant two-way interaction between posture and grip type. Results from this experiment were used to model the effect of these variables on operator discomfort and performance.