Efficacy of a long-pulsed 1064-nm Nd:YAG laser in acute scar redness

Background The initial redness of the scar on a postoperative suture site is a natural phenomenon that fades over time. However, with a long period of redness, patients complain about cosmetic discomfort, and the possibility of pigmentation changes is induced. We investigated the use of a long-pulsed 1064 nm Nd:YAG laser as a noninvasive treatment for improving the redness of these scars. Methods A retrospective chart review was conducted on 36 patients who underwent excision of a nevus on the face. Fourteen patients received laser treatment and another 22 patients used only scar management ointment. Patients were followed up 1 week after the sutures were removed. The photographic images taken at the time of suture removal and 2 months later were reviewed. The evaluation was performed on a 7-point scale by adding the Japan Scar Workshop (JSW) scar scale’s redness and erythema scores. Results The average initial JSW scar scale score of the treatment group was 4.6, and that of the nontreatment group was 4.2. When the re-evaluation was performed 2 months later, the score of the treatment group decreased to 2.2 and that of the nontreatment group decreased to 3.1. The difference in the JSW scar scale between the treatment group and the nontreatment group according to laser performance was statistically significant (P=0.03). Conclusions The treatment method with a long-pulsed 1064 nm Nd:YAG laser that is less invasive and has a quick effect can be a good alternative for improving this initial scar redness

Investigation of the mechanism of the anomalous Hall effects in Cr2Te3/(BiSb)2(TeSe)3 heterostructure

The interplay between ferromagnetism and the non-trivial topology has unveiled intriguing phases in the transport of charges and spins. For example, it is consistently observed the so-called topological Hall effect (THE) featuring a hump structure in the curve of the Hall resistance (Rxy) vs. a magnetic field (H) of a heterostructure consisting of a ferromagnet (FM) and a topological insulator (TI). The origin of the hump structure is still controversial between the topological Hall effect model and the multi-component anomalous Hall effect (AHE) model. In this work, we have investigated a heterostructure consisting of BixSb2-xTeySe3-y (BSTS) and Cr2Te3 (CT), which are well-known TI and two-dimensional FM, respectively. By using the so-called minor-loop measurement, we have found that the hump structure observed in the CT/BSTS is more likely to originate from two AHE channels. Moreover, by analyzing the scaling behavior of each amplitude of two AHE with the longitudinal resistivities of CT and BSTS, we have found that one AHE is attributed to the extrinsic contribution of CT while the other is due to the intrinsic contribution of BSTS. It implies that the proximity-induced ferromagnetic layer inside BSTS serves as a source of the intrinsic AHE, resulting in the hump structure explained by the two AHE model

Investigation of the mechanism of the anomalous Hall effects in Cr2Te3/(BiSb)2(TeSe)3 heterostructure

The interplay between ferromagnetism and the non-trivial topology has unveiled intriguing phases in the transport of charges and spins. For example, it is consistently observed the so-called topological Hall effect (THE) featuring a hump structure in the curve of the Hall resistance (Rxy) vs. a magnetic field (H) of a heterostructure consisting of a ferromagnet (FM) and a topological insulator (TI). The origin of the hump structure is still controversial between the topological Hall effect model and the multi-component anomalous Hall effect (AHE) model. In this work, we have investigated a heterostructure consisting of BixSb2−xTeySe3−y (BSTS) and Cr2Te3 (CT), which are well-known TI and two-dimensional FM, respectively. By using the so-called minor-loop measurement, we have found that the hump structure observed in the CT/BSTS is more likely to originate from two AHE channels. Moreover, by analyzing the scaling behavior of each amplitude of two AHE with the longitudinal resistivities of CT and BSTS, we have found that one AHE is attributed to the extrinsic contribution of CT while the other is due to the intrinsic contribution of BSTS. It implies that the proximity-induced ferromagnetic layer inside BSTS serves as a source of the intrinsic AHE, resulting in the hump structure explained by the two AHE model.This work was supported by the Korea Institute of Science and Technol‑ogy (KIST) through 2E31550 and by the National Research Foundation program through NRF-2021M3F3A2A03017782, 2021M3F3A2A01037814, 2021M3F3A2A01037738, 2021R1A2C3011450, and 2020R1A2C200373211,[Innovative Talent Education Program for Smart City] by MOLI

Investigation of CO₂ seeps at the crystal geyser site using numerical modeling with geochemistry

textCarbon Dioxide (CO₂) sequestration requires that the injected CO₂ be permanently trapped in the subsurface and not leak from the target location. To accomplish this, it is important to understand the main mechanisms associated with CO₂ flow and transport in the subsurface once CO₂ is injected. In this work CO₂ seeps at the Crystal Geyser site were studied using modeling and simulation to determine how CO₂ geochemically reacts with formation brines and how these interactions impact the migration of CO₂. Furthermore different scenarios for CO₂ migration and seepage along the Grand Wash fault are studied and the possible outcomes for these different scenarios are documented. The GEM (Generalized Equation-of-State Model) from CMG Ltd. was used to perform the simulation studies. A 2-D model was built without geochemical reactions to mainly study the mechanism associated with dissolution of CO₂ gas. The process of CO₂ release from the brine as the fluid mixture flows up along the fault was modeled. Then, 3-D models with geochemical reactions were built for CO₂ migration corresponding to two different sources of CO₂ - deep crustal ₂ and CO₂-dissolved in groundwater. In both these cases, CO₂ reacted with the aqueous components and minerals of the formation and caused carbonate mineralization. In the case of deep crustal CO₂ source, there were vertical patterns of calcite mineralization simulated along the fault that indicated that calcite mineralization might be localized to isolated vertical flow paths due to vertical channeling of CO₂ from the crust. In the case of CO₂-dissolved groundwater flowing along the sandstone layers, calcite mineralization is spread over the entire fault surface. In this case, the groundwater flow is interrupted by the fault and there is vertical flow along the fault until a permeable sandstone layer is encountered on the other side of the fault. This vertical migration of CO₂-saturated brine causes a release in pressure and subsequent ex-solution of CO₂. As a result, modeling allowed us to establish difference in surface expression of CO₂ leakage due to two different CO₂ migrations scenarios along the fault and helped develop a scheme for selecting appropriate model for CO₂ leakage based on surface observation of travertine mounds. A key observation at the Crystal Geyser site is the lateral migration of CO₂ seep sites over time. These migrations have been confirmed by isotope studies. In this modeling study, the mechanism for migration of seep sites was studied. A model for permeability reduction due to precipitation of calcite was developed. It is shown using percolation calculations that flow re-routing due to permeability alterations can result in lateral migration of CO₂ seeps at rates comparable to those established by isotope dating.Petroleum and Geosystems Engineerin

Near-Field Sound Localization Based on the Small Profile Monaural Structure

The acoustic wave around a sound source in the near-field area presents unconventional properties in the temporal, spectral, and spatial domains due to the propagation mechanism. This paper investigates a near-field sound localizer in a small profile structure with a single microphone. The asymmetric structure around the microphone provides a distinctive spectral variation that can be recognized by the dedicated algorithm for directional localization. The physical structure consists of ten pipes of different lengths in a vertical fashion and rectangular wings positioned between the pipes in radial directions. The sound from an individual direction travels through the nearest open pipe, which generates the particular fundamental frequency according to the acoustic resonance. The Cepstral parameter is modified to evaluate the fundamental frequency. Once the system estimates the fundamental frequency of the received signal, the length of arrival and angle of arrival (AoA) are derived by the designed model. From an azimuthal distance of 3–15 cm from the outer body of the pipes, the extensive acoustic experiments with a 3D-printed structure show that the direct and side directions deliver average hit rates of 89% and 73%, respectively. The closer positions to the system demonstrate higher accuracy, and the overall hit rate performance is 78% up to 15 cm away from the structure body

Near-Field Sound Localization Based on the Small Profile Monaural Structure

The acoustic wave around a sound source in the near-field area presents unconventional properties in the temporal, spectral, and spatial domains due to the propagation mechanism. This paper investigates a near-field sound localizer in a small profile structure with a single microphone. The asymmetric structure around the microphone provides a distinctive spectral variation that can be recognized by the dedicated algorithm for directional localization. The physical structure consists of ten pipes of different lengths in a vertical fashion and rectangular wings positioned between the pipes in radial directions. The sound from an individual direction travels through the nearest open pipe, which generates the particular fundamental frequency according to the acoustic resonance. The Cepstral parameter is modified to evaluate the fundamental frequency. Once the system estimates the fundamental frequency of the received signal, the length of arrival and angle of arrival (AoA) are derived by the designed model. From an azimuthal distance of 3–15 cm from the outer body of the pipes, the extensive acoustic experiments with a 3D-printed structure show that the direct and side directions deliver average hit rates of 89% and 73%, respectively. The closer positions to the system demonstrate higher accuracy, and the overall hit rate performance is 78% up to 15 cm away from the structure body

A CDMA and AMPS Handset Power Amplifier based on Load Modulation Technique

A new MMIC PA for Cellular & AMPS handsets based on the asymmetric power combining scheme of Doherty amplifier has been developed to boost the efficiency at a low power level. The amplifier has two modes of operation, low and high power modes. At a low power mode, only the main amplifier generates output power and at a high power mode, both the main and auxiliary amplifiers are operational, combining the power efficiently by the load modulation. For the CDMA environment, the amplifier at the low power mode exhibits PAE of 35% and ACLR less than 31dBc at 18.6dBm and the high power mode exhibits PAE of 37.7% and ACLR of 31dBc at 28.4dBm. For the AMPS mode operation, the amplifier delivers 21dBm with PAE of 41.7% and 30.3dBm with 43% in low mode and high mode, respectively

A novel bias circuit with temperature and process compensation for RFIC

Temperature and process variations have become key issues in design of integrated circuits using deep submicron technologies.In the RF front-end circuitry, these characteristics must be compensated to maintain acceptable performance across all process corners and throughout the temperature variations. This article proposes a new bias circuit technique to compensate the variations by adding a single NMOS to the normally bias circuit. A 2.4GHz and 5.2GHz LNAs with the proposed bias circuit have the power gain variation (S21) of only 0.3 dB for the -40 to 85 degrees C temperature range in a 65nm RF CMOS process. (c) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:26942697, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27170X110sciescopu