Search Results (22)

Background: Variability and low volume yield in breast aesthetic outcomes utilizing fat grafting promoted a search for surgical technique improvement. Aim: Using evidence-based information to optimize a surgical technique for aesthetic breast augmentation using stem cell-enriched fat grafting. Methods: Retrospective study of consecutive women (n = 118) from 2008 to 2025 requesting breast fat grafting using centrifugation–filtration fat processing combined with platelet-rich plasma and autologous adipose-derived stem cell-enriched fat. Results: Most surgical indications were for primary breast augmentation (65.8%), followed by fat grafting after implant removal (13.6%), during or after mammoplasty (13.6%), or simultaneously with implant exchange (12.7%). The mean volume per breast of purified, enriched fat grafted was 192 to 206 cc. Each patient had fat grafted into the subcutaneous plane with some patients having additional fat placed submuscularly in those without a dual plane or submuscularly placed implant, or where an implant capsule was absent. Most patients were either very satisfied or satisfied (95.8%), with 4.2% dissatisfied. Those dissatisfied were mainly those with insufficient breast volume and one with a suspected atypical mycobacteria infection. There was a 11.9% complication rate, with seroma formation at the harvested site the most common at 5.1% (n = 6). Palpable fibrotic areas were second in frequency at 3.4% (n = 4), but with no instances of breast oil cyst formation. The average number of fat grafting sessions per indication was only one, with 6.8% requesting a second staged fat grafting procedure. The revision procedures were only in patients with a sole augmentation indication, except for one mastopexy patient with severe breast size asymmetry. An estimated 75–85% grafted volume take was confirmed by a previous diagnostic ultrasound measurement study. Conclusions: Breast fat grafting incorporating learned knowledge of optimal harvesting, processing, storing, enrichment, and administration techniques yielded superior consistent breast enhancement aesthetic outcomes with a high patient and surgeon satisfaction rate through increased adipocyte survival, while minimizing complications including a low incidence of fibrotic areas and no oil cyst formation. Full article

A terahertz photonic crystal fiber with two sensing channels was designed. Graphene coated on the micro-grooves in the cladding was used as plasma material to introduce tunability. The dispersion relation, mode coupling, and sensing characteristics of the fiber were studied using the finite element method. Ultrahigh sensitivity of 2.014 THz/RIU and 0.734 GHz/°C were obtained for analytes with refractive index in the range of 1.33 to 1.4 and environment temperature in the range of 10–60 °C, respectively. Refractive index resolution can reach the order of 10⁻⁵. The dual parameter simultaneous detection, dynamic tunable characteristics, and working in the low-frequency range of terahertz enable the designed photonic crystal fiber to have application prospects in the field of biosensing. Full article

This study presents a novel approach for improving the interfacial adhesion between Nd–Fe–B spherical magnetic powders and polyamide 12 (PA12) in polymer-bonded magnets using plasma treatments. By applying radio frequency plasma to the magnetic powder and low-pressure microwave plasma to PA12, we achieved a notable enhancement in the mechanical and environmental stability of fused deposition modeling (FDM)-printed Nd-Fe-B/PA12 magnets. The densities of the FDM-printed materials ranged from 92% to 94% of their theoretical values, with magnetic remanence (B_r) ranging from 85% to 89% of the theoretical values across all batches. The dual plasma-treated batch demonstrated an optimal mechanical profile with an elastic modulus of 578 MPa and the highest ductility at 21%, along with a tensile strength range of 6 to 7 MPa across all batches. Flexural testing indicated that this batch also achieved the highest flexural strength of 15 MPa with a strain of 5%. Environmental stability assessments confirmed that applied plasma treatments did not compromise resistance to corrosion, evidenced by negligible flux loss in both hygrothermal and bulk corrosion tests. These results highlight plasma treatment’s potential to enhance mechanical strength, magnetic performance, and environmental stability. Full article

Equatorial plasma bubbles (EPBs) occur frequently in low-latitude areas and have a non-negligible impact on navigation satellite signals. To systematically analyze the effects of a single EPB event on multi-frequency signals of GPS, Galileo, GLONASS, and BDS, all-sky airglow images over South China are jointly used to visually determine the EPB structure and depletion degree. The results reveal that scintillations, or GNSS signal fluctuations, are directly linked to EPBs and that the intensity of scintillation is positively correlated with the airglow depletion intensity. The center of the airglow depletion often corresponds to stronger GNSS scintillation, while the edge of the bubble, which is considered to have the largest density gradient, corresponds to relatively smaller scintillation instead. This work also systematically analyzes the responses of multi-constellation and multi-frequency signals to EPBs. The results show that the L2 and L5 frequencies are more susceptible than the L1 frequency is. For different constellations, Galileo’s signal has the best tracking stability during an EPB event compared with GPS, GLONASS, and BDS. The results provide a reference for dual-frequency signal selection in precise positioning or TEC calculation, that is, L1C and L2L for GPS, L1C and L5Q for Galileo, L1P and L2C for GLONASS, and L1P and L5P for BDS. Notably, BDS-2 is significantly weaker than BDS-3. And inclined geosynchronous orbit (IGSO) satellites have abnormal data error rates, which should be related to the special signal path trajectory of the IGSO satellite. Full article

A tunable dual-band terahertz sensor based on graphene is proposed. The sensor consists of a metal bottom layer, a middle dielectric layer, and single-layer graphene patterned with four strips on the top. The numerical simulations results show that the proposed sensor exhibits two significant absorption peaks at 2.58 THz and 6.07 THz. The corresponding absorption rates are as high as nearly 100% and 98%, respectively. The corresponding quality factor (Q) value is 11.8 at 2.58 THz and 29.6 at 6.07 THz. By adjusting the external electric field or chemical doping of graphene, the positions of the dual-frequency resonance peak can be dynamically tuned. The excitation of plasma resonance in graphene can illustrate the mechanism of the sensor. To verify the practical application of the device, the terahertz response of different kinds and different thicknesses of the analyte is investigated and analyzed. A phenomenon of obvious frequency shifts of the two resonance peaks can be observed. Therefore, the proposed sensor has great potential applications in terahertz fields, such as material characterization, medical diagnosis, and environmental monitoring. Full article

The inverter module serves as a critical component in the conversion of electrical energy within arc plasma power sources, exerting a profound influence on the overall performance and stability of the power supply. Consequently, the meticulous design and precise control of the inverter module are of paramount importance in ensuring the effective operation and application of arc plasma power sources. This paper introduces a dual-closed-loop control system, integrating a voltage outer loop with a current inner loop, as the cornerstone of its inverter module design. It also undertook a comprehensive comparative analysis of various voltage-control strategies, encompassing four control methods (PI, PID, PR, QPR) and two modulation techniques (bipolar modulation and unipolar, carrier-based modulation) under diverse operating conditions. Additionally, simulation experiments were conducted on a prototype 10 kW inverter module using the Matlab/Simulink simulation platform, with evaluation criteria including waveform tracking performance, voltage waveform distortion rate, and steady-state error. The results indicate that in low-frequency operating conditions, the voltage-control strategy employing QPR control plus unipolar, carrier-based modulation, and in high-frequency operating conditions, the voltage-control strategy utilizing PI control plus unipolar, carrier-based modulation exhibited superior waveform tracking performance. The waveform distortion rates were measured at below 0.47% and 4.2%, respectively, aligning perfectly with the stringent standards of IEEE 519. This research provides valuable theoretical support and practical guidance for future engineering endeavors in the field of inverters. Full article

Gold nanoparticles have been extensively studied due to their unique optical and electronic properties which make them attractive for a wide range of applications in biomedicine, electronics, and catalysis. Over the past decade, atmospheric pressure plasma jets in contact with a liquid have emerged as a sustainable and environmentally friendly approach for synthesizing stable and precisely controlled dispersions. Within the context of plasma jet/liquid configurations, researchers have explored various power sources, ranging from kHz frequencies to nanopulse regimes. In this study, we investigated the effects of coupling two distinct power supplies: a high-voltage micropulse and a radio frequency (RF) generator. The variations within the plasma induced by this coupling were explored by optical and electrical measurements. Our findings indicated a transition from a bullet plasma propagation mechanism to a capacitive coupling mechanism upon the introduction of RF energy. The impact on the production of metal nanoparticles was also examined as a function of the radio frequency power and of two distinct process gases, namely helium and argon. The characterization of gold nanoparticles included UV-visible spectroscopy, dynamic light scattering, and scanning electron microscopy. The results showed that the size distribution depended on the type of process gas used and on the power supplies coupling. In particular, the incorporation of RF power alongside the micropulse led to a decrease in both average particle size and distribution width. The comparison of the different set up suggested that the current density can influence the particle size distribution, highlighting the potential advantages of the use of a dual-frequency atmospheric pressure plasma jet configuration. Full article

In this paper, we proposed a small transparent thin film antenna for a wireless capsule endoscopy system. The transparent thin film antenna is needed to provide a clear 360° broad-sight view of the wireless capsule system in the future. Furthermore, the transparent thin film is critical for performing the dual-polarized antenna operating at 2.45 GHz. The proposed transparent thin film uses the nano-alignment process to further achieve low resistivity from 3.78 × 10⁻⁴ Ω-cm to 9.14 × 10⁻⁵ Ω-cm and improves the transparency by over 70%. The nano-alignment process includes periodic electrodes with AC signals that can effectively rearrange the nano-material into an ordered arrangement, enhancing the thin film’s microwave characteristics. Due to applying to the capsule endoscopy system, the ability of water resistance is also considered in this design. Therefore, the O₂ plasma treatment is used to improve the water contact angle from 76° to 31°, measured on the surface of the thin film. The proposed transparent antenna is designed to have a center frequency of 2.45 GHz, a bandwidth of 855 MHz, and an antenna gain of −26.3 dBi, and is helpful for capsule endoscopy systems. Full article

As the process complexity has been increased to overcome challenges in plasma etching, individual control of internal plasma parameters for process optimization has attracted attention. This study investigated the individual contribution of internal parameters, the ion energy and flux, on high-aspect ratio SiO${}_2$ etching characteristics for various trench widths in a dual-frequency capacitively coupled plasma system with Ar/C${}_4$F${}_8$ gases. We established an individual control window of ion flux and energy by adjusting dual-frequency power sources and measuring the electron density and self-bias voltage. We separately varied the ion flux and energy with the same ratio from the reference condition and found that the increase in ion energy shows higher etching rate enhancement than that in the ion flux with the same increase ratio in a 200 nm pattern width. Based on a volume-averaged plasma model analysis, the weak contribution of the ion flux results from the increase in heavy radicals, which is inevitably accompanied with the increase in the ion flux and forms a fluorocarbon film, preventing etching. At the 60 nm pattern width, the etching stops at the reference condition and it remains despite increasing ion energy, which implies the surface charging-induced etching stops. The etching, however, slightly increased with the increasing ion flux from the reference condition, revealing the surface charge removal accompanied with conducting fluorocarbon film formation by heavy radicals. In addition, the entrance width of an amorphous carbon layer (ACL) mask enlarges with increasing ion energy, whereas it relatively remains constant with that of ion energy. These findings can be utilized to optimize the SiO${}_2$ etching process in high-aspect ratio etching applications. Full article

Single-shot ultrafast multi-frame imaging technology plays a crucial role in the observation of laser-induced plasma. However, there are many challenges in the application of laser processing, such as technology fusion and imaging stability. To provide a stable and reliable observation method, we propose an ultrafast single-shot multi-frame imaging technology based on wavelength polarization multiplexing. Through the frequency doubling and birefringence effects of the BBO and the quartz crystal, the 800 nm femtosecond laser pulse was frequency doubled to 400 nm, and a sequence of probe sub-pulses with dual-wavelength and different polarization was generated. The coaxial propagation and framing imaging of multi-frequency pulses provided stable imaging quality and clarity, as well as high temporal/spatial resolution (200 fs and 228 lp/mm). In the experiments involving femtosecond laser-induced plasma propagation, the probe sub-pulses measured their time intervals by capturing the same results. Specifically, the measured time intervals were 200 fs between the same color pulses and 1 ps between the adjacent different. Finally, based on the obtained system time resolution, we observed and revealed the evolution mechanism of femtosecond laser-induced air plasma filaments, the multifilament propagation of femtosecond laser in fused silica, and the influence mechanism of air ionization on laser-induced shock waves. Full article

The bone mass increases that occur during the period of childhood are of great significance for maximizing the peak bone mass in adults and preventing for osteoporosis. Studies have reported that VA can improve the bone health in adults. Moreover, limited studies have assessed such associations in children. In this cross-sectional study including 426 children, we assessed the children’s plasma retinol concentration by liquid chromatography–mass spectrometry and the dietary intake of VA and carotenoids using a structured Food Frequency Questionnaire. Their bone mineral content and bone mineral density (BMD) were measured using dual-energy X-ray absorptiometry. After adjusting for potential confounders, the restricted cubic spline revealed an inverted U-shaped association between plasma retinol concentration and BMD; the estimated effects on the TBLH BMD per μmol/L increase in the plasma retinol concentration were 1.79 × 10⁻² g/cm² below 1.24 μmol/L and −5.78 × 10⁻³ g/cm² above this point (p for non-linearity = 0.046). A multiple linear regression analysis revealed a positive association between the plasma retinol concentration and the TBLH BMC (β = 1.89, 95% CI: 1.64 × 10⁻¹–3.62, p = 0.032). In conclusion, an appropriate plasma retinol concentration and greater intakes of dietary VA and β-carotene may enhance the bone mineral status of children who are aged 6–9 years. Full article

Introduction: The risk of obesity in children with Down syndrome is high. Undoubtedly, proper nutrition plays an important role in the prevention of excess body weight and is associated with a reduction of metabolic complications. The aim of the study was to assess the problem of disturbances in the nutritional status and eating habits of children with DS. Methods: A total of 39 patients were included in the study. The nutritional status was assessed by anthropometric tests and Dual X-ray Absorptiometry. Eating habits were assessed using the Child Eating Behavior Questionnaire and the Food Frequency Questionnaire. Blood samples were taken to determine the oxidative stress and lipid parameters. Results: Obesity was recognized in 15% of subjects and 23% were overweight. Children that were overweight were characterized by higher levels of triglycerides, atherogenic index of plasma, and apoA2 and apoE levels. Fat mass, fat mass/height² index, and visceral fat mass correlated with thiobarbituric acid reactive substances and advanced oxidative protein product level. The analysis of the Child Eating Behavior Questionnaire showed that children struggling with being overweight were more interested in food compared to those with normal body weight. A positive correlation was identified between waist circumference and food interest categories. Insufficient consumption of dairy products, vegetables, whole grain products, as well as fruits, seeds, nuts, and fatty fish was noted. Patients were less likely to consume products that are a good source of mono- and polyunsaturated fatty acids. Conclusions: In children with Down syndrome and obesity, disturbances in lipid and oxidative stress parameters are observed. Abnormal eating habits in all children with Down syndrome regardless of their nutritional status were noted. Proper nutritional education, nutritional control, and management of metabolic problems are essential in this group of patients. Full article

A new Doppler radar using millimeter-waves in the Ka-band, named the “dual-comb Doppler reflectometer”, has been developed to measure the turbulence intensity and its velocity in high-temperature plasmas. For the realization of a fusion power generation, it is very important to know the spatial structure of turbulence, which is the cause of plasma confinement degradation. As a non-invasive and high spatial resolution measurement method for this purpose, we apply a multi-frequency Doppler radar especially with simultaneous multi-point measurement using a frequency comb. The newly developed method of synchronizing two frequency combs allows a lower intermediate frequency (IF) than the previously developed frequency comb radar, lowering the bandwidth of the data acquisition system and enabling low-cost, long-duration plasma measurements. In the current dual-comb radar system, IF bandwidth is less than 0.5 GHz; it used to be 8 GHz for the entire Ka-band probing. We applied this system to the high-temperature plasma experimental device, the Large Helical Device (LHD), and, to demonstrate this system, verified that it shows time variation similar to that of the existing Doppler radar measurements. Full article

A dual-frequency plasma source has many advantages in applications. In this paper, a dual-frequency microwave plasma source is presented. This microwave plasma source is based on a coaxial transmission line without the resonator, and it can be operated in a wide band frequency region. Two microwaves are inputted from two ports into the plasma reactor: one is used firstly to excite the plasma and the other one is used to adjust plasma characteristics. Based on the COMSOL Multiphysics simulation, the experiment is carried out. In the experimental investigation, the plasma electron density and electron temperature can be controlled, respectively, by feeding in different frequencies from the second port, causing the particles at different energy levels to present different frequencies. This exploratory research improves the operation frequency of dual-frequency microwave plasma sources from RF to microwave. Full article

The change in electrode impedance of semiconductor equipment due to repetitive processes is a major issue that creates process drift. In the current plasma etch chamber with a dual-frequency power system, the high-powered radio frequency (RF) source contributes to the enhancement of the plasma density, and the low-frequency bias power at the bottom electrode is adopted to enhance the injected ion energy in the plasma. The impedance control of the top electrode in dual-frequency capacity coupled plasma limits the impedance matching capability of the RF matching system because it only considers the high-frequency RF source. To control the precise impedance in dual-frequency semiconductor equipment, independent impedance control is required for each frequency. In this study, the impedance corresponding to a specific frequency was independently controlled using L (inductor) and C (capacitor). A 60 MHz stop filter and VVC were used to control 2 MHz impedance at a specific point, and a 2 MHz stop filter and VVC were used to control 60 MHz impedance. In the case of 2 MHz impedance control, the 2 MHz impedance changed from 10.9−j893 to 0.3−j62 and the 60 MHz impedance did not change. When controlling the 60 MHz impedance, the 60 MHz impedance changed from 0.33 + j26.53 to 0.2 + j190 and the 2 MHz impedance did not change. The designed LC circuits cover the impedance of 60 and 2 MHz separately and are verified by the change in the capacitance of the vacuum variable capacitors implemented in the RF impedance matching system. Full article